In  assembling  the  informa¬ 
tion  contained  in  this  bulletin, 
we  have  consulted  the  follow¬ 
ing  authorities; 

United  States  Bureau  of  Standards 
Test  Data. 

Transmission  of  Heat  Through 
Building  Materials.  Bulletin 
No.  3,  Engineering  Dept.,  University 
of  Minnesota,  by  Prof.  F.  B.  Rowley. 

Mechanical  Equipment  of  Build¬ 
ings;  Professors  Willard  &  Harding, 
University  of  Illinois. 

Transmission  of  Insulating  M.vte- 
RiALS.  Data  compiled  by  American 
Society  of  Refrigerating  Engineers. 

Investigation  of  Methods  for 
Testing  Heat  Insulators,  Bul¬ 
letin  No.  33,  Engineering  Depart¬ 
ment,  Pennsylvania  State  College, 
by  Professor  E.  F.  Grundhofer. 

Test  Data  of  Armour  Institute, 
Chicago,  by  Professor  J.  C.  Peebles. 


The  Acoustics  of  Buildings,  by  Prof. 
F.R.  Watson,  University  of  Illinois. 


The  insulation  of  this  home  was  a 

straight  Flax-li-nnin  specification.  Fac-  j  IVAN  DISK  and  CLAIR  W.  DITCHY 

tors  for  heat  losses,  radiation  requirements  Architects  -  Detroit,  Michigan 

and  fuel  consumption  are  given  on  pages 
26  and  27  of  this  book. 


Tla^c-li-nmn 

THE  CORRECT  BUILDING  INSULATION  AND  SOUND  CONTROL  MATERIAL  * 


A  treatise  on  Insulation  for  build¬ 
ings,  compiled  for  ready  reference 
for  Architects  and  Engineers. 


Copyright,  1927 

FLAX-LI-NUM  INSULATING  COMPANY 
ST.  PAUL,  MINN. 

PRINTED  IN  U.  S.  A. 


TABLE 


O  F 


CONTENTS 


Contents 


Flax-li-imiii.  Its  Origin,  Development  and  Uses  -  --  --  --  --  --  Page  5 

Wli  at  Is  a  Correct  Insulation?  -  --  --  --  --  --  --  --  --  --  --  5 

The  Correct  lUiilding  Insnlation  -  --  --  --  --  --  --  --  --  --  -  (> 

What  Flax-li-niini  Is  -  --  --  --  --  --  --  --  --  --  --  --  --  (> 

The  Flax-li-nnm  Insulating  Method  -  --  --  --  --  --  --  --  --  --  7 

Heat  Transfer  and  Its  Measurement  -  --  --  --  --  --  --  --  --  -  8 

II  eat  Losses  From  Buildings  -  --  --  --  --  --  --  --  --  --  --  -  9 

F.  fleet  of  Surface  Resistances  on  Efficiency  -  --  --  --  --  --  --  --  -l() 

Heat  Loss  Through  House  Roofs  -  --  --  --  --  --  --  --  --  --  -10 

The  Determination  of  Transmission  Co-efficients  -  --  --  --  --  --  --  H 

Formulae  For  Standard  Walls  and  Roofs  -  --  --  --  --  --  --  --  -  13 

Standard  Wall  and  Roof  Sections  -  --  --  --  --  --  --  --  --  --  -  14 

Determining  Net  Fuel  Savings  on  Actual  Houses  -  --  --  --  --  --  --18 

Heat  Losses  on  Bungalow  Type  Houses  - 

H  eat  Losses  on  Larger  Type  Houses  -  --  --  --  --  --  --  --  --  - 

Suggestions  for  Specifying  Heat  Insulation  -  --  --  --  --  --  --  --  - 

List  of  Flax-li-num  Specifications  -  --  --  --  --  --  --  --  --  --  -29 

Thermal  Insulation  Specifications  -  --  --  --  --  --  --  --  --  --  -31 

Flax-li-num  Sound  Control  -  --  --  --  --  --  --  --  --  --  --  --38 

Sound  Control  Specifications  -  --  --  --  --  --  --  --  --  --  --  -4i 

Industrial  Roof  Insulation  -  --  --  --  --  --  --  --  --  --  --  --  48 

Heat  Transmission  Values  for  Roofs  -  50 

Humidity  Control  Chart  and  Data  -  --  --  --  --  --  --  --  --  --  51 

Aj)artment  House  Roof  Data  -  --  --  --  --  --  --  --  --  --  --  -  50 

Radiation  Reciuirements  and  Fuel  Losses  on  Industrial  Roofs,  of  Concrete,  Wood 
and  Steel  -  --  --  --  --  --  --  --  --  --  --  --  --  --  -- 

Roof  S]3ecifications  -  --  --  --  --  --  --  --  --  --  --  --  --  -55 

Flax-li-num  Test  Data  -  --  --  --  --  --  --  --  --  --  --  --  -  58 

Flax-li-num  Stock  Sizes  -  --  --  --  --  .-  --  --  --  --  --  --  -59 


Flax-li-num  Radiation  Conij)utation  Chart  --------  Back  Inside  Cover 


HEAT  INSULATION  FOR  HOUSES 


Plax-ll-num 


F  EVERY  building  in  the  United  States  today  were  insulated  there  would 
be  conserved  each  year  at  least  30%  of  the  Nation’s  annual  coal  hill.  It  has 
been  conservatively  estimated  that  there  is  wasted  in  fuel  every  year  in  the 
United  States  the  enormous  sum  of  $450,000,000  because  of  poor,  or  un¬ 
scientific  construction  of  house  walls  and  roof.  This  tremendous  National  waste  has  of 
late  years  had  the  attention  of  leading  engineers  and  conservationists.  Notable  among 
whom  were  the  late  Chas.  P.  Steinmetz,  consulting  ing  huts  of  thatched  grass,  and  the  thicker  and 


engineer  of  the  General  Electric  Company,  and  Ex- 
President  Theodore  Roosevelt.  Dr.  Steinmetz  in 
discussing  the  subject  said,  “Our  present  structures 
are  causing  annual  leakage  costs  of  literally  mil¬ 
lions  of  dollars’  worth  of  heat.  The  house  of  the 
future  will  be  scientifically  built  from  the  stand¬ 
point  of  heating.” 

Begmning  of  the  Insulation  Idea 

The  idea  of  heat  insulation  from  the  standpoint 
of  comfort  is  a  primitive  one.  People  of  earlier 
times  endeavored  to  secure  comfort  for  their  places 
of  abode  by  various  methods.  Perhaps  the  most 
notable  of  early  methods  being  the  “Wattle  and 
Daub”  construction  of  the  New  England  colonists, 
who  filled  the  open  spaces  between  uprights  in  their 
houses  with  a  mixture  of  straw  and  mud.  Primitive 
methods  are  known  today,  and  a  degree  of  comfort 
is  secured  bv  both  the  Eskimo  and  the  South  Sea 
Islander  by  the  application  of  natural  insulation 
principles.  In  the  far  north  the  Eskimo  builds  his 
igloo  with  insulation  only — snow  blocks  which  con¬ 
tain  millions  of  entrapped  air  cells — and  keeps  com- 
fortablv  warm  with  a  small  seal-oil  flame.  At  the 
other  extreme  of  temperature  the  aborigines  of  the 
tropics  found  that  they  could  enjoy  a  degree  of 
comfortable  relief  from  the  burning  sun,  by  build- 


firmer  the  thatch,  the  cooler  was  the  interior.  These 
are  applications  of  natural  insulation  principles. 

Modeini  Construction  and  Insulation 

As  building  methods  developed,  new  fuel  sup¬ 
plies  opened  up,  and  more  efficient  methods  of  con¬ 
suming  fuel  came  into  general  use,  the  tendency  of 
home  construction  has  been  toward  units  that  have 
been  increasingly  better  protection  against  rain, 
snow  and  wind,  but  not  against  the  passage  of  heat. 
As  fuel  costs  advanced,  insulation  again  began  to 
force  itself  on  the  consciousness  of  the  building 
public,  so  that  back-plaster  came  into  vogue  and 
remained  common  practice  until  the  early  part  of 
the  present  century,  when  serious  attention  was 
first  really  given  to  a  search  for  and  development  of 
a  really  efficient  insulating  material. 

What  Is  a  Correct  Building  Insulation^ 

A  correct  and  efficient  building  insulation  must 
possess  the  following  characteristics:  First — it 

must  be  a  far  better  heat-stop  than  any  of  the  corn- 
building  materials.  Second — It  should  be 


mon 


made  of  permanent  raw  materials  and  in  perma¬ 
nent  form.  Third — It  should  be  easy  to  handle 
and  install,  since  the  application  is  as  important  as 
the  material.  Fourth — Insulation  should  make 


4 


6 


Heat  Insulation  for  Houses 


possible  fuel  savings  that  will  represent  a  sizable  re-  Flax-li-nnm  very  definitely  brings  the  following 
turn  on  the  investment.  economies: 


The  Correct  Building  Insulation 

Flax-li-nnm  has  been  called  the  correct  building 
insulation  because  it  meets  fully  each  and  every  one 
of  the  above  recinirements.  Fir.^t — Flax-li-nnm  is 
an  efficient  non-conductor  of  heat  when  compared 
with  familiar  building  materials.  One  inch  of  Flax- 
li-nnm  stops  as  much  heat  as  sixteen  inches  of 
brick,  or  twenty-seven  inches  of  concrete. 


1  of  Flax'li  -ntun  - 16  of  Brick  andi  Mortar  or  s27of  SoliJ  Concroto 


Showing  the  relative  heat  stopping  qualities  of 
common  building  materials. 


Second — Flax-li-nnm  is  made  from  nature’s 
toughest  and  longest  lived  vegetable  fibre.  It  is 
impervious  to  decay  and  in  its  semi-rigid  form  it  is 
guaranteed  to  remain  in  place  at  full  efficiency  as 
long  as  a  building  stands. 

Third — Flax-li-nnm  is  decidedly  easy  to  handle 
and  install.  It  comes  in  flanged  sheets  ready  to 
apply  between  studdings  on  wood  construction  and 
in  flat  sheets  for  roof  and  ceiling  insulation.  It  is 
semi-rigid  in  form,  not  subject  to  breakage,  buck¬ 
ling  or  warping,  and  is  flexible  enough  to  adapt  it¬ 
self  to  the  shrinkage  of  construction  members  and 
settlement  of  the  building  without  impairing  in  any 
way  its  efficiency  or  its  application. 

Fourth — Flax-li-num  makes  an  attractive  invest¬ 
ment.  Because  it  so  materially  reduces  heat  losses, 
it  makes  j)ossible  a  reduction  in  radiation  require¬ 
ments,  and  this  saving  offsets  a  large  ])ortion  of  the 
original  insulation  cost.  The  full  cost  of  Flax-li-num 
can  be  regained  in  fuel  savings  within  three  years  and 
thereafter,  as  long  as  the  building  stands,  the  an¬ 
nual  saving  comes  to  the  owner  as  an  excellent 
dividend  on  his  Flax-li-num  investment. 


1.  Economv  of  Fuel. 

_ t _ 

*2.  Economv  in  Radiation. 

_ _ 

3.  Piconomv  effected  bv  Health  Conditions. 

%■ 


Flax-li-num  Introduced  in  1909 

Flax-li-num  was  developed  by  the  late  Mr.  Geb- 
liard  Bohn,  pioneer  manufacturer  and  owner  of  im¬ 
portant  patents  covering  refrigerators  and  refrig¬ 
erator  car  construction.  Beginning  in  1909  Flax- 
li-num  was  tried  and  tested  in  these  vigorous  fields. 
It  was  installed  in  thousands  of  refrigerator  cars, 
where  constant  vibration  and  racking  test  the  dur¬ 
ability  of  the  insulating  material  to  the  utmost. 
Since  that  year  the  transportation  of  fruits,  meats, 
and  perishable  merchandise  has  been  successfully 
carried  on  bv  American  railroads  in  thousands  of 
F'lax-li-num  insulated  refrigerator  cars. 

That  Flax-li-num  has  met  fully  the  exacting  re- 
(juirements  of  this  rigid  service  is  proven  by  the 
fact  that  today  Flax-li-num  is  the  Standard  in¬ 
sulation  on  many  of  America’s  largest  refrigerator 
transportation  lines. 

Flax-li-num  finds  extensive  use  in  the  insulation 
of  high  class  domestic  and  market  refrigerators, 
iceless  ice  cream  shipping  containers  and  kindred 
products. 


What  Flax-li-num  Is 

Flax-li-num  is  a  semi-rigid  board,  felted  from  the 
long  tough  fibres  of  the  Flax  plant.  Flax  is  a 
natural  insulator.  Miscroscopic  inspection  reveals 
that  the  stalks  are  made  up  of  a  multitude  of  tiny 
air  cells,  each  separated  from  the  other  by  thin  tis¬ 
sue  walls.  The  long  fibres  interlacing  in  the  sheet 
create  additional  cells,  and  the  multiplicity  of  these 
minute  air  cells  accounts  for  the  efficiency  of  Flax- 
li-num  as  a  resistant  to  the  passage  of  heat.  No 
artificial  binder  is  required  to  make  a  strong  build¬ 
ing  material  from  the  Flax.  The  interlacing  of  the 
long  fibrous  material  giving  the  necessary  binding 
ciualities  to  hold  together  the  “felted”  sheet. 


Heat  Insulation  for  Houses 


7 


Tlie  Flax  plant  does  not  rot,  as  do  the  straws 
from  cereal  grains,  such  as  wheat  and  rye.  For  this 
reason  the  Flax  straw  on  farms  in  flax  growing 
countries  was  burned  since  it  could  serve  no  useful 
purpose  on  the  farm.  It  is  this  inherent  quality  of 
the  flax  fibre  that  gives  to  Flax-li-num  its  long  life 
and  the  assurance  that  the  insulation  will  last  as 
long  as  the  building  stands.  In  the  process  of  man¬ 
ufacture  Flax-li-num  is  chemically  treated  to  re¬ 
move  the  natural  oils  and  gums  from  the  fibre. 
This  chemical  treatment  renders  Flax-li-num  ver¬ 
min  and  rodent  proof. 

Not  a  Substitute  or  Dual-Purpose 

Matet'ial 

Flax-li-num  today  occupies  the  same  ground  as 
when  it  was  introduced.  It  gives  the  utmost  in  in¬ 
sulating  efficiency,  combined  with  rugged  durabil¬ 
ity,  ease  of  application  and  guaranteed  long  life 
It  is  guaranteed  by  the  makers  never  to  fall  down 
or  become  displaced  in  the  walls  of  any  building. 
Because  it  is  not  a  rigid  board  it  cannot  warp, 
break  or  crack,  either  when  buildings  settle  or  be¬ 
cause  of  the  expansion  and  contraction  of  its  own 
fibres.  It  does  not  substitute  for  the  accepted  wood 
or  metal  lath,  nor  for  sheathing  or  any  other  part 
of  the  construction.  Consequently  its  makers  are 
not  forced  to  cater  to  dual  uses,  which  weaken  the 
vital  use — heat  insulation.  The  fact  that  Flax-li- 
num  to  date  lines  more  houses  than  all  other  insu¬ 
lations  combined,  that  it  is  the  standard  insulation 
used  in  American  Railway  refrigerator  cars,  and 
that  it  is  standard  equipment  on  the  highest  grade 
refrigerators,  is  conclusive  proof  of  the  soundness 
of  Flax-li-num  as  a  product,  and  of  the  correctness 
of  its  recommended  application. 

The  Flax-li-num  hisidating  Method 

At  the  same  time  that  Flax-li-num  was  being  de¬ 
veloped  as  a  material,  there  was  being  developed 
with  it  an  insulation  method.  The  material  and 
method  are  closely  allied,  and  this  brings  us  to  a 
consideration  of  the  various  Flax-li-num  applica¬ 
tions  in  walls  and  roofs  of  frame,  brick,  hollow  tile 


or  veneer  construction.  The  Flax-li-num  method 
calls  for  the  application  of  flanged  material  midway 
between  the  inner  and  outer  portions  of  frame 
walls.  Certain  of  our  specifications  for  brick  and 
tile,  which  are  fully  covered  in  this  volume,  call  for 
the  use  of  fiat  sheets,  but  each  application  has  been 
so  designed  that  the  owner  will  receive  the  full 
benefit  of  surface  resistances,  as  described  in  detail 
in  the  chapter  on  “Heat  Losses  from  Buildings.” 

The  methods  of  applying  insulation,  as  covered  in 
the  accompanying  specifications,  were  all  developed 
by  the  Flax-li-num  Insulating  Company  and  have 
been  standard  with  them  for  a  period  of  more  than 
fifteen  years. 

It  will  be  noted  that  all  Flax-li-num  specifica¬ 
tions  for  ceiling  and  roof  insulation  call  for  one  inch 
of  material.  Our  Engineering  Department  was  the 
first  to  recognize  that  the  old  rule-of-thumb  method 
of  calculating  heat  losses  through  roofs  was  wrong, 
and  that  the  combined  ceiling,  attic  space  and  roof 
should  be  considered  as  a  compound  wall  in  calcu¬ 
lating  heat  losses.  We  were  also  the  first  to  recog¬ 
nize  the  fact  that  heat  losses  through  the  ceiling 
and  roof  were  practically  double  those  of  side  wall 
losses,  and  since  heat  transmission  is  inversely  pro¬ 
portional  to  the  thickness  of  the  insulating  mate¬ 
rial,  we  established  upon  a  scientific  basis  the  need 
for  one  inch  of  insulation  in  ceilings  and  roofs. 
Having  taken  this  stand  there  was  a  long  period 
when  the  Flax-li-num  Company  was  the  only  in¬ 
sulation  manufacturer  recognizing  this  application. 

It  is  the  purpose  of  this  bulletin  to  set  up  definite 
standards  of  comfort  and  economv  for  walls  and 

t' 

roofs.  To  do  this  each  wall  is  figured  according  to 
an  approved  formula,  and  assigned  its  correct  heat 
transmission  coefficient.  Thus,  frame,  stucco, 
brick,  hollow  tile,  or  any  special  construction  is  re¬ 
duced,  from  a  comfort  and  economy  standpoint,  to 
the  common  denominator  of  a  transmission  coeffi¬ 
cient,  and  comparison  readily  settles  between  com¬ 
peting  constructions.  Many  of  the  walls  listed  here 
have  been  actually  tested  with  exact  scientific  ap¬ 
paratus  and  results  given  may  be  readily  proven, 
either  by  formula  or  direct  experiment. 


8 


Heat  Insulation  for  Houses 


Heat  Transfer  and  Its  Measurement 


HE  principles  underlying  heat  transfer  are  comparatively  simple.  They 
involve  for  the  most  part  only  familiar  elementary  conceptions  of  matter 
and  energy.  Some  of  them  are  so  elementary  that  they  seem  frequently 
to  be  overlooked  when  considering  practical  problems,  which  might  he 
greatly  simplified  by  their  application.  A  brief  review  of  known  facts  governing  heat 
travel  is  here  given,  as  a  reminder  of  the  salient  points  and  their  application  to  the 


study  of  Insulating  Materials. 

Heat — a  DefiJiitioii 

Heat  lias  long  been  known  to  be  a  form  of  energy 
and  not  a  substance.  Modern  theories  as  to  the 
exact  nature  of  heat  conceive  it  to  be  a  motion  or 
agitation  of  the  molecules  of  which  every  body  is 
composed.  Every  substance  contains  some  heat 
and  to  say  that  a  body  is  “cold”  means  simply  that 
it  contains  a  relatively  small  amount  of  heat  (mole¬ 
cular  motion). 

Measurement  of  Heat 

In  measuring  heat  there  are  two  quantities  to  be 
considered;  the  intensity  and  the  amount.  A  small 
piece  of  white-hot  metal  may  not  contain  as  great 
an  amount  of  heat  as  a  pail  of  warm  water,  but  the 
intensity  of  the  heat  in  the  former  is  much  greater. 
The  measurement  of  intensity  or  temperature  is 
usually  based  upon  some  arbitrary  scale  such  as  the 
Fahrenheit  or  Centigrade  thermometers. 

The  British  Thermal  Unit 

Heat  must  be  measured  by  the  effect  which  it 
produces  upon  some  substance.  The  unit  of  heat 
used  in  modern  engineering  practice  is  the  amount 
needed  to  raise  the  temperature  of  a  pound  of  water 
one  degree  Fahrenheit.  This  is  called  the  British 
thermal  unit  and  is  denoted  by  the  symbol  B.  t.  u. 
As  this  quantity  is  not  exactly  the  same  at  all  tem¬ 
peratures  it  is  necessary  to  specify  further  a  defi¬ 
nite  temperature  at  which  the  unit  is  to  be  estab¬ 
lished.  The  practice  of  different  authorities  varies 
in  this  regard,  but  the  B.  t.  u.  established  by  Marks 


and  Davis  is  becoming  generally  used.  Thus  it  is 
defined  as  “the  one  hundred  and  eightieth  part  of 
the  heat  necessary  to  raise  the  temperature  of  one 
pound  of  Water  from  32°  to  212°  F.” 

The  Transmission  of  Heat 

Heat  mav  be  transmitted  in  three  wavs:  bv  ra- 

ty  V 

diation,  by  conduction  and  by  convection. 

Radiation — Heat  is  transmitted  by  radiation 
by  what  is  supposed  to  be  a  motion  or  vibration  of 
the  ether  which  is  believed  to  pervade  all  space. 
Radiant  heat  follows  the  same  physical  laws  as 
radiant  light,  traveling  in  straight  lines.  We  may 
have  heat  “shadows”  just  as  we  have  light  shadows 
and  the  intensity  of  radiant  heat  is  inversely  pro¬ 
portional  to  the  square  of  the  distance  from  the 
source  from  which  it  comes. 

Some  substances  are  transparent  to  heat  rays 
and  others  absorb  them.  Gasses  are  almost  per¬ 
fectly  transparent  to  radiant  heat  while  substances 
as  Flax-li-num  are  almost  opaque  to  it.  Radiant 
heat  does  not  affect  the  medium  through  which  it 
passes.  For  example,  the  atmosphere  is  not  percep¬ 
tibly  warmed  by  the  sun’s  radiant  heat  transmit¬ 
ted  to  the  earth. 

Conduction — If  one  part  of  a  body  is  at  a  higher 
temperature  than  another  part  there  will  be  a  flow 
of  heat  through  the  body.  The  transmission  of 
heat  is  this  manner  is  known  as  conduction.  A 
familiar  example  of  this  phenomenon  is  the  flow  of 
heat  along  an  iron  bar,  one  end  of  which  is  heated 
in  a  fire.  The  abilitv  of  different  materials  to  con- 
duct  heat  differs  considerably.  Metals  are  the  best 


Heat  Insulation  for  Houses 


9 


conductors  of  heat,  while  such  materials  as  Flax- 
li-num  are  very  poor  conductors. 

Convection — When  a  body  is  in  contact  with  a 
fluid  at  a  lower  temperature,  the  envelope  of  fluid 
surrounding  the  body  becomes  heated  by  conduc¬ 
tion.  As  this  fluid  envelope  is  heated  its  density  de¬ 
creases  and  it  is  forced  to  rise,  giving  place  to  the 
colder  fluid  from  below.  A  continuous  current  is 
thus  created  and  maintained  over  the  surface  of  the 
body.  This  process  of  heat  transfer  is  called  con¬ 
vection.  It  should  be  noted  that  the  heat  actually 
leaves  the  hot  bodv  bv  condnction  from  its  surface 

I  I 


to  the  fluid  in  contact  with  it.  The  essential  char¬ 
acteristic  of  the  process  of  convection  is  the  con¬ 
tinuous  renewal  of  the  fluid  layer  at  the  surface  of 
contact. 

Heat  may  also  be  transmitted  from  a  fluid  to  a 
solid  by  convection  as  well  as  from  a  solid  to  a 
fluid.  An  example  of  this  process  is  the  transfer  of 
heat  from  the  warm  air  of  a  room  to  the  cold  out¬ 
side  walls.  The  air,  upon  giving  up  its  heat,  in¬ 
creases  in  density  and  falls,  giving  place  to  warmer 
air  from  above  and  producing  a  continuous  down¬ 
ward  current. 


Heat  Losses  From  Buildings 


HEN  the  interior  of  any  building  is  maintained  at  a  temperature  higher 
than  that  of  the  outside  air  there  is  a  continual  loss  of  heat  from  the 
building.  The  functions  of  a  heating  system  are,  first,  to  raise  the  tem¬ 
perature  of  the  interior  of  the  building  to  the  point  desired  and,  second, 
to  maintain  this  temperature  by  supplying  sufficient  heat  to  replace  that  lost  from 
the  building.  The  determination  of  the  amount  of  heat  lost  from  the  building  under 
maximum  demand  is  the  first  step  in  designing  the 


heating  system. 


Methods  of  Preventing  Heat  Losses 


Before  taking  up  the  methods  of  calculating  heat 
loss  it  is  necessary  to  consider  first  the  manner  in 
which  heat  may  be  lost  from  a  building. 

Buildings  lose  heat,  first,  by  a  combination  of 
conduction,  convection  and  radiation  through  the 
walls  and  roof;  second,  by  actual  air  leakage  or 
“infiltration”;  third,  by  ventilation.  Windows  in¬ 
crease  the  loss  by  radiation  and  conduction.  The 
character  of  walls  and  roof  determine  the  amount 
of  loss  through  them. 

It  is  important  to  recognize  the  fact  that  “tight” 
construction  (painting-in  window  frames,  calk¬ 
ing,  lining  houses  with  paper,  etc.)  affects  only  the 
“infiltration”  and  cannot  cut  down  the  great  losses 
due  to  the  three  sources  of  heat  travel.  No  matter 
how  “tight”  a  sheet  metal  shed  may  be  it  will  al¬ 
ways  l)e  frigid  in  winter  and  unbearabl,y  hot  in 
the  summer  months. 


There  are  several  practical  methods  of  stopping 
heat  losses.  The  thermos  bottle  makes  use  of  two 
methods,  one  to  prevent  transmission  by  radiation 
and  the  other  to  prevent  transmission  by  convec¬ 
tion.  Radiation  has  been  stopped  by  silvering  the 
inner  surfaces  of  the  bottle  so  as  to  reflect  the 
radiant  rays.  Convection  has  been  stopped  by 
creating  a  vacuum  between  the  inner  and  outer 
bottles.  The  only  method  of  heat  travel  not  fully 
stopped  by  this  construction  is  conduction.  There 
is  a  slight  amount  of  conduction  through  the  glass 
at  the  stopper.  Obviously  these  methods  cannot 
be  used  in  buildings.  The  method  best  adapted  to 
buildings  is  that  of  forming  tiny  air  cells  in  the  tex¬ 
ture  of  a  material  and  incorporating  this  material 
into  the  walls  and  roof  of  the  structure.  All  re¬ 
frigerators,  cooling  rooms  and  railroad  refrigerator 
cars  operate  by  the  application  of  this  latter  meth- 


10 


Heat  Insulation  for  Houses 


0(1.  Somewhere  in  the  walls  and  roof  they  have 
an  “INSULATION,”  a  material  containing  these 
fiui/  air  spaces. 

Note  that  we  have  emphasized  the  word  tiny  in 
the  foregoing  paragraph.  The  large  air  chambers 
commonly  found  in  ordinary  frame  walls,  as  well 
as  in  walls  of  hollow  tile  or  similar  constructions, 
are  not  insulation.  Air  itself  is  not  an  insulator. 
In  the  best  of  construction  there  will  always  be 
some  circulation  of  air,  and  where  air  circulates 
there  is  a  transfer  of  heat.  By  tiny  air  cells  we 
mean  minute  chambers  such  as  contained  within 
the  texture  of  Flax-li-num.  Such  cells  retard  the 
transmission  of  heat  because  there  is  no  circula¬ 
tion  of  air  from  one  to  the  other. 

Surface  Resistances 

Air  spaces  do  affect  heat  flow  in  another  way,  as 
shown  by  the  diagrams  (1  to  3  on  page  12).  Heat 
encounters  a  resistance  as  it  enters  and  as  it  leaves 
an}^  substance.  Thus  every  air  space  in  a  wall 
or  roof  adds  two  “surface  resistances”  to  the  total. 
The  “surface  resistances”  of  materials  differ  widel3y 
and  thev  must  be  taken  into  consideration  when 
building. 

Wh  ere  the  insulation 
divides  the  air  space  in  a 
wall  there  are  produced 
two  surface  resistances 
more  than  though  the 
same  insulation  were  plac¬ 
ed  against  the  sheathing  or 
against  the  plaster.  The 
transmission  of  the  re¬ 
sulting  wall  is  therefore 
lower. 

Thus  we  explain  the  reason  behind  the  Flax-li- 
num  s])ecifications  No.  4-A  and  13-A  (pages  31  and 
33)  which  show  Flax-li-num  dividing  the  air  space 
between  the  studding  and  separated  from  both  plas¬ 
ter  and  sheathing  in  the  wall.  These  specifications, 
beside  their  ])ractical  features  of  space  saving  and 
economical  installation,  allow  Flax-li-num  to  func¬ 
tion  at  its  maximum  efhciency  bj^  taking  advantage 
of  the  full  surface  effects  of  each  member  of  the 


wall.  This  is  a  utilization  of  natural  laws  securing 
an  added  benefit. 

It  is  a  mistake  to  appl\"  heat  insulation  so  tliat 
these  surface  effects  are  lost.  To  plaster  directh"  on 
insulation  causes  the  loss  of  two  surface  drops;  to 
apph'  insulation  over  sheathing  on  the  outside  and 
cover  with  siding  also  causes  the  loss  of  two  surface 
drops.  Flax-li-num  specifications  are  designed  to 
produce  maximum  efficiency  on  the  job. 

Heat  Lost  Through  Roofs 

The  same  formula  used  to  determine  heat  losses 
through  walls  applies  to  house  roofs.  The  roof 
construction,  as  well  as  that  of  the  top  stor^-  ceil¬ 
ing,  affects  the  heat  flow  and  should  be  considered. 
For  \"ears  the  popular  method  of  determining  this 
loss  was  to  assume  an  average  winter  temperature 
in  the  attic  or  loft,  and  then  consider  onlv  the 
transmission  from  the  upstairs  rooms  to  the  attic. 
This  attic  temperature,  for  instance  was  often 
taken  at  40  degrees,  where  the  average  temperature 
outside  was  being  taken  many  degrees  lower.  The 
fact  that  there  was  a  constant  heat  loss  from  the 
attic  which  varied  with  the  construction  of  the  roof 
above  it  was  entirelj^  overlooked. 

Heat  passed  from  upstairs  rooms  into  the  attic, 
and  from  the  attic  to  the  out-of-doors.  The  attic 
forms  an  open  space  which  adds  two  surface  re¬ 
sistances  to  the  total  heat  resistance  of  the  roof  and 
ceiling  combination.  Considering  this  combina¬ 
tion  as  a  compound  wall  eliminates  an  old  error, 
and  brings  computed  heat  losses  nearer  the  actual. 
This  method  is  followed  b}^  Professor  Frank  B. 
Rowley  in  his  Bulletin,  “Transmission  of  Heat 
Through  Building  Materials f''  published  October 
26,  1923,  b}^  the  University  of  Mi  nnesota. 

The  6  formulae  given  on  page  13  accurately 
gauge  all  heat  losses  that  occur  b^-  conduction  in 
straight  lines  through  the  ceiling  and  roof.  They 
are  correct  without  adjustment  so  long  as  there  is 
no  variation  in  construction  at  the  eave  line.  How¬ 
ever,  where  the  attic  floor  is  used,  as  in  ceilings  A, 
B,  E  and  F,  (page  17)  a  very  sizable  heat  loss  occurs 
from  the  ceiling  into  the  attic  which  does  not  go 
through  this  floor,  but  travels  around  it  b}^  con- 


Heat  Insulation  for  Houses 


11 


vection,  and  up  through  the  open  spaces  between 
tlie  rafters,  which  are  not  as  a  rule  covered  by  the 


attic  floor.  The  illustration,  Figure  1,  shows  the 
manner  of  this  heat  loss. 

In  computing  the  heat  loss  from  ceilings  where 
this  construction  is  in  use  let  us  assume  the  heat 
resistive  qualities  of  the  floor  (not  any  other  part 
of  the  roof  and  ceiling  combination)  as  cut  in  two 
for  a  distance  of  six  feet  out  from  the  walls. 

The  formula  for  this  O-foot  strip,  thus,  becomes: 

] 

K  - - 

1  1.125  1  1  .75  1  1  .75  1 

—  + - H - H - +  —  +  —  +  —  +  —  +  — 

1.2  1.2  1.1  1.1  1.2  1.1  1.3  8.3  1.3 

2 

1 

or  K  = - =  .220 

1.511 

The  heat  loss  from  the  roof  of  the  house  shown 
on  page  19  is  computed  on  this  basis. 


The  Determination  of  Transmission 

Coefficients 


F  HOUSE  walls  and  roofs  were  made  up  of  solid  masses  of  a  single  ma¬ 
terial  the  heat  resistance  of  any  wall  would  be  a  simple  problem  of 
addition.  Knowing  the  resistance  coefficient  of  a  given  unit  thick¬ 
ness  we  could  add  and  subtract  to  obtain  the  result  for  a  wall  or  roof  as 
specified.  Walls,  however,  are  made  up  of  layers  of  different  materials,  each  with  a 
different  transmission  coefficient  and  are  further  complicated  by  air  spaces  like  those 


commonlv  found  in  frame  and  tile  construction. 

Some  basic  formula  is  necessary  to  enable  us  to 
arrive  at  the  correct  heat  transmission  of  any  wall 
or  roof.  This  formula  must  be  theoretically  sound, 
and  must  check  with  actual  tests  in  the  laboratories 
of  reliable  experimental  engineers;  as  well  as  with 
observations  on  actual  jobs. 

The  Formula  of  Willard  a7id  Lichty 

The  formula  universally  used  by  architects  and 
engineers,  is  that  of  Messrs.  Willard  and  Liciity, 
as  published  in  University  of  Illinois  Bulletin  No. 
102,  and  as  covered  in  Harding  and  Willard’s 


handbook  ’‘'Mechanical  Equipment  of  Buildings." 
No  space  is  available  here  for  the  proof  of  this  for¬ 
mula.  Full  explanation  of  its  origin  and  deriva¬ 
tion  is  contained  in  the  publications  above  men¬ 
tioned.  It  has  been  accepted  and  successfully 
applied  by  heating  engineers  for  a  period  of  years, 
and  experimental  tests  upon  wall  sections  check 
accurately  with  the  results  computed  from  the 
formula. 

Development  of  the  formula  for  simple  and  com¬ 
pound  walls  is  shown  in  the  three  diagrams  on  the 
following  page.  The  key  is  as  follows: 


12 


Heat  Insulation  for  Houses 


K  =^heat  transmission  coefficient  of  wall  desired  in 
15.  t.  u.  per  sq.  ft.  per  dg.  F.  per  hr. 

C  -conductivity  coefficient  of  material  making  up 
wall  (per  inch  of  thickness)  in  B.  t.  u.  per  sq. 
ft.  per  degree  F.  per  hr. 

Si  —inside  surface  coefficient  of  material  making  up 
wall  in  B.  t.  u.  per  sq.  ft.  per  dg.  F.  per  hr. 

So  -  outside  surface  coefficient  of  material  making 
up  wall  in  B.  t.  u.  per  sq.  ft.  per  dg.  F.  per  hr. 


X  -thickness  in  inches. 

The  factors,  So,  Si,  S2,  S3,  S4,  and  Cl,  C2,  Cs,  etc., 
are  known  from  tabulations  of  tests  and  experi¬ 
ments. 

The  figure  (.210)  gives  us  the  amount  of  heat  in 
B.  t.  u.’s  transmitted  through  a  square  foot  of  the 
Brick  Veneer  wall  shown  below  for  every  degree 
difference  between  the  outside  and  inside  tempera¬ 
ture  for  every  hour  of  time. 


FIG.  1 


FIG.  2 


Heat  Transmission  Thru  Simple  Wall  Heat  Transmission  Thru  Wall  of  More  Than  One 

Material,  But  Without  Air  Spaces 


1 

K  = - 

1  X  1 

-  -| - -j - 

So  C  Si 


FIG.  3 

Heat  Transmission  Thru  Wall  Made  Up  of  Various 
Materials  and  Containing  Air  Spaces 


1  X  1  X  X  1  1  X  1 

- 1 - \ - H - 1 - ^ - 1 - 1 - 1 - 

So  Cl  S2  C2  Cs  S3  Si  Cl  Si 

See  wall  A-2 — opposite  page 


A  group  of  typical  small  homes  showing  the  snow  melted  from  the  roofs  due  to  lack  of  roof  insulation.  1"  of 
Flax-li-num  would  have  prevented  the  heat  leaking  through  the  roofs  and  made  a  substantial  reduction  in  fuel  require¬ 
ments  on  each  of  these  homes.  Note  that  the  snow  remains  on  the  unheated  porches. 


Heat  Insulation  for  Houses 


13 


Transmission  Coefficients  of  Walls 


Stucco  Walls — ^See  Page  14 


Wall  A-1 

1  1 

K=  - - = - =  .242 

1  .75  1  .02  75  1  1  .75  1  4.137 

- 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 

3.9  8,3  1  3  4  1  2  1  4  1  3  8.3  1  3 

Wall  B-1 

1  1 

K= -  ■  - - = - =.14(i 


1  75  1  .02  .75  1  1  1  .75  1  G.S42 

- 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 

3  9  8  3  1.3  .4  1.2  1.4  .37  1.3  8.3  1.3 


Wall  C-l 

1  1 

1  .75  .5  1  1  1  75  1  3.490 

- 1 - 1 - 1 - \ - 1 - 1 - 1 - 

3.9  8.3  1  2  1.3  1  4  1.3  8.3  1.3 


Brick  Walls — Continued 

Wall  D-2 

1 

K= - 

14  1111 

- 1 - 1 - 1 - 1 - 1 - 

4.2  5  .99  .99  1.3  .31 

Wall  E-2 

1 

1  13  1  1  .75  1 

- 1 - 1 - 1 - 1 - 1 - 

4.2  5  1  3  1  3  8.3  1  3 

Wall  F-2 

1 

K= - 

1  13  1  1 

- 1 - 1 - 1 - 

4.2  5  1.3  31 


1 

- =141 

7.058 


1 

- =.191 

5  238 


1 

- =  .14(1 

(i.83,S 


Wall  D-1 

1  1 

K= - = - =  .161 

1  .75  .5  1  1  1  1  .75  1  6.220 

- 1 - 1 - 1 - ] - 1 - 1 - 1 - 1 - 

3  9  8.3  1  2  1.3  1  4  .37  1.3  8.3  1.3 


Wall  E-1 

1  1 

K= - = - =  .357 

1  1.25  1  1  .75  1  2.805 

- 1 - 1 - 1 - 1 - 1 - 

3  9  8.3  1  3  1.3  8  3  1.3 

Wall  F-1 

1  1 

K= - = - =181 

1  1.25  1  1  1  .75  1  5.515 

—  + - +  —  +  —  +  —  +  —  +  — 


3.9  8.3  1.3  .37  1.3  8.3  1.3 

Brick  Walls — See  Page  15 


Wall  A-2 

1  1 

K= - = - =  .210 

1  4  1  .02  .75  1  1  ,75  1  4.769 

- 1 - 1 - 1 - 1 - 1 - 1 - ] - 1 - 

4.2  5  1  4  4  1.2  1.4  1.3  8.3  1  3 

Wall  B-2 

1  1 

K= - = - =  ,133 

1  4  1  .02  .75  1  1  1  .75  1  7.499 


- 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 

4.2  5  1.4  4  1  2  1.4  .37  1.3  8.3  1  3 


Frame  Walls — See  Page  16 


Wall  A-3 

1 

1  1  1.125  .02  1  1  .75  1 

- 1 - 1-. - 1 - 1 - 1 - 1 - 1 - 

4  2  1.4  1.2  ,4  1  4  1  3  8.3  13 

2 

Wall  B-3 

1 

K= - - - 

1  1  1.125  .02  1  1  1  .75  1 

- 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 

4.2  1.4  1.2  .4  1.4  .37  1.3  8.3  1.3 

2 


1 

= - =  .255 

3.929 


1 

- =  .151 

6.639 


Wall  C-3 

1  1 

K=  - - - - = - =  .216 

1  1  1.125  .02  1  1  4.628 

- 1 - 1 - 1 - 1 - ^ - 

4.2  1.4  1.2  .4  1.4  .43 

2 


Wall  D-3 

1 

K= - 

1  1  1.125  .02  1  1  1 

- 1 - \ - 1 - 1 - 1 - \ - 

4.2  1.4  1.2  4  .37  1.4  .43 


=  —  =  .136 
7.338 


2 


Wall  E-3 

1  1 

K= - - = - =  .229 

1  .375  1  1  .75  1  4.368 

- 1 - 1 - 1 - 1 - 1 - 

4.2  1.2  .456  1.3  8.3  1.3 


Wall  C-2 

1  1 

K  = - - = - =  .  255 

1  4  1  1  .75  1  3.918 

- 1 - 1 - 1 - 1 - 1 - 

4.2  5  .99  .99  8  3  1.3 


Wall  F-3 

1 

K=  - - 

1  .375  1  1  1  .75  1 

I - 1 - 1 - 1 - [ - 1 - 

4.2  1.2  .456  .37  1.3  8  3  1.3 


1 

- =  .141 

7.078 


Transmission  Coefficients  of  Roofs 


Roof  A-1 


1  1.125  1  1  .75  1  1  .75  1  5  577 

- 1 - 1 - 1 - 1 - 1 - 1 - ^ - 1 - 

4.2  1.2  1.4  1.4  1.2  1.4  1.3  8.3  1.3 


See  Page  17 

Roof  D-1 


.179  K= - - - 

1  1.125  1  1  1 

- 1 - 1 - 1 - 1 - 

4  2  1.2  1.4  .245  1.3 


1 


.75  1 

- 1 - 

8.3  1.3 


Roof  B-1 

1 

K= - 

1  1.125  1  1  .75  1 

- 1 - 1 - 1 - 1 - 1 - 

4.2  1.2  1.4  1.4  1.2  1.4 


1 

- = - =  .104 

1  1  .75  1  9.657 

- 1 - 1 - 1 - 

245  1.3  8.3  1.3 


Roof  E-1 

K= - 

1  .5  1  .02  .75  1 

- \ - 1 - 1 - \ - 1 - 

3.9  5  1.4  .4  1.2  1.4 


1 


1  .75  1  1  .75  1 

- 1 - 1 - \ - 1 - 1 - 

1.4  1.2  1  4  1.3  8  3  1.3 


1 

- =  .132 

7.602 


1 

-  =  163 

6  147 


Roof  C-l 

K= - 


1 


1  1.125  1  1  .75  1 

- 1 - 1 - 1 - i - 1 - 

4.2  12  1.4  1.3  8.3  1.3 


1 

- =  .281 

3.522 


Roof  F-1 

1  1 

X= - - - - =  -  -  =  .098 

1  5  1  .02  .75  1  1  .75  1  1  1  75  1  10.229 

- 1 - 1 - \ - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 

3.9  5  1.4  .4  1.2  1.4  1.4  1.2  1.4  .245  1.3  83  1  3 


14 


Heat  Insulation  for  Houses 


Heat  Transmission  of  Stucco  Walls 


%"  Plaster,  wood  lath 

2"x4"  Studding 

6"  D®.M  Sheathing 

Building  paper 

l"x2"  Furring  strips 

Portland  stucco  on 
metal  lath 


Plaster,  wood  lath 
2"x4"  Studding 
1/2"  Flax-li-num 

6"  Dca,M  Sheathing 

Building  paper 

l"x2''  Furring  strips 

Portland  stucco  on 
metal  lath 


Wall  A-1 

Transmission  .  .  .  . 


K=.242 


Wall  B-1 

Transmission  .  .  .  . 


K=.146 


%"  Plaster,  wood  lath 

2"x4"  Studding 

l"x6"  Byrkett  sheathing 

Portland  stucco  on 
Byrkett  sheathing 


%"  Plaster,  wood  lath 
2"x4"  Studding 
1/2"  Flax-Ii-num 

l"x6"  Byrkett  sheathing 

Portland  stucco  on 
Byrkett  sheathing 


Wall  C-1 

Transmission  .  .  .  . 


K=287 


Wall  D-1 

Transmission  .  .  .  . 


K=.161 


%"  Plaster,  wood  lath 

2"x4"  Studding 

Portland  stucco  on 
metal  lath 

%"  Back  plastering 
between  studs 


Plaster,  wood  lath 
2"x4"  Studding 

V2"  Flax-Ii-num 

Portland  stucco  on 
metal  lath 

Back  plastering 
between  studs 


Wall  E-1 

Transmission  .  .  .  . 


K=.357 


Wall  F-1 

Transmission  .  .  .  . 


K=181 


Heat  Insulation  for  Houses 


15 


Heat  Transmission  of  Brick  and  Tile  Walls 


Plaster,  wood  lath 
2"x4''  Studding 
6"  D^s-M  Sheathing 
Building  paper 
Face  Brick 


^/b'  Plaster,  wood  lath 
Studding 

V2"  Flax-li-num 

D®.M  Sheathing 
Building  paper 
Face  Brick 


Wall  A-2 

Transmission 


K=.210 


Wall  B-2 

Transmission 


K=.133 


Vb  Plaster,  on  Tile 
8"x5"xl2"  Hollow  Tile 
Face  Brick 


^/b"  Plaster,  on 

Flax*li-num  Keyboard 

as  plaster  base 

V'xl''  Furring  strips 
8"x5"xl2"  Hollow  Tile 
Face  Brick 


Wall  C-2 

Transmission  .  .  .  . 


K=.255 


Wall  D-2 

Transmission 


K-.141 


^b'  Plaster,  wood  lath 
T'x2"  Furring  strips 
Common  Brick 
Face  Brick 


Plaster,  on 

Flax-li*num  Keyboard 

as  plaster  base 

l"x2''  Furring  strips 
Common  Brick 
Face  Brick 


Wall  E-2 

Transmission 


K=.191 


Wall  F-2 

Transmission 


K=.146 


16 


Heat  Insulation  for  Houses 


Heat  Transmission  of  Frame  Walls 


%"  Plaster,  wood  lath  1 

^  z' 

2"x4"  Studding  1 

i 

6"  D®-M  Sheathing  4 

/ 

Building  paper  W 

Siding  k 

W 

t| 

% 

Plaster,  wood  lath 
2"x4"  Studding 
1/2"  Flax'li-num 

6"  D®.M  Sheathing 
Building  paper 
Siding 


Wall  A-3 

Transmission  .  ,  .  . 


K=.255 


Wall  B-3 

Transmission  .  .  .  . 


K=.151 


/ 


/ 


V— t 


%"  Plaster 

Lumber  substitute 
as  plaster  base 

2"x4"  Studding 

6"  D®.M  Sheathing 

Building  paper 

Siding 


%"  Plaster 

7,6  Lumber  substitute 
as  plaster  base 

2"x4''  Studding 

^2"  Flax'li-num 

6"  D<®.M  Sheathing 
Building  paper 
Siding 


Wall  C-3 

Transmission  .  .  .  . 


K=.216 


Wall  D-3 

Transmission  .  .  .  . 


K=.136 


Plaster,  wood  lath 

2"x4"  Studding 

7,6  Lumber  substitute 
as  sheathing 

Siding 


Wall  E-3 

Transmission  .  .  .  . 


K=.229 


Plaster,  wood  lath  TjJ 

2'^x4"  Studding  h 

i/ 

1/2"  Flax-ll-num  W 

[/ 

\  V 

7,6  Lumber  substitute  1' 

as  sheathing  1 

Siding  A 

i 

;/ 

Wall  F-3 

Transmission  .  .  .  , 


Heat  Insulation  for  Houses 


17 


Heat  Transmission  of  Roofs 


Ceiling  and  Roof  A 

Transmission . 


K=.179 


Wood  shingles 
l"  Roof  boards 
2"xA"  Roof  rafters 
2"x4''  Collar  beams 


%  Plaster  on  wood  lath 


Ceiling  and  Roof  C 

Transmission . 


K=.284 


Ornamental  roof  tile 
1"  Roof  boards  -paper 
2"x6"  Roof  rafters 
T'x6"  D<®-M  Flooring 
2"x8"  Ceiling  joists 


Plaster  on  wood  lath 


Ceiling  and  Roof  E 

Transmission . 


K=.163 


Wood  shingles 
l"  Roof  boards 
2"x4"  Roof  rafters 
l"x6"  D®-M  Flooring 
2"x6"  Ceiling  joists 
1"  Flax-li*num 

Furring  strips  on  joists 
Plaster  on  wood  lath 


Ceiling  and  Roof  B 

Transmission . 


K=.104 


Wood  shingles 
1"  Roof  boards 
2"x4"  Roof  rafters 
2''x4"  Collar  beams 

1"  Flax*li*num 

Furring  strips 

Ts"  Plaster  on  wood  lath 


Ceiling  and  Roof  D 

Transmission . 


K=.132 


Ornamental  roof  tile 
1"  Roof  boards  -paper 
2"x6"  Roof  rafters 
T'x6"  D'S-M  Flooring 
2"x8"  Ceiling  joists 
1"  Flax-li-num 


%"  Plaster  on  wood  lath 


Ceiling  and  Roof  F 

Transmission . 


K=.098 


18 


Heat  Insulation  for  Houses 


Determining  the  Net  Fuel  Saving  on 

Actual  Houses 


EAT  insulation  cannot  save  all  the  heat  wasted  in  a  house.  Neither  “in¬ 
filtration”  nor  ventilation  is  eliminated  by  heat  insulation.  Losses  due 
to  conduction  and  radiation  through  windows  are  not  affected.  The  ques¬ 
tion  arises,  “How  much  is  the  net  saving  on  an  actual  house?” 

The  net  saving  varies  with  every  plan.  To  illustrate  the  saving  and  to  show  that  it  is 
real  and  tangible,  three  houses  are  here  shown.  Each  has  been  considered  with  each 


of  the  walls  shown  on  pages  14, 15  and  16,  and  with 
insulated  and  uninsulated  roofs  shown  on  page  17. 
Total  heat  losses  have  been  computed  for  the  de¬ 
termination  of  radiation.  The  insulated  houses 
show  a  marked  reduction  in  radiation  requirements, 
which  are  directly  proportional  to  the  total  heat 
loss.  Fuel  consumption  based  on  heat  losses,  as¬ 
suming  an  average  temperature  difference  for  the 
vicinity  of  St.  Paul,  Minnesota. 

The  heating  season  is  taken  at  210  days  with  an 
average  temperature  difference  of  38°  Fahrenheit 
over  this  period  {U.  S.  Weather  Bureau  Reports) 
or  7980  Degree-days.  A  correction  must  be  made 
for  the  locality  in  which  the  building  is  to  be 
erected. 

The  heat  transmission  used  for  walls  and  roofs 
are  those  shown  on  the  charts,  pages  14, 15, 16  and 
17,  the  derivation  of  which  has  been  given  on  page 
13.  The  houses  were  assumed  to  have  double  sash 
which  has  a  heat  transmission  .45  B.  t.  u. 

Value  of  hot  water  radiation  is  taken  as  156  B. 
t.  u.  per  square  foot.  Maximum  heat  loss,  to  de¬ 
termine  size  of  radiators  and  of  necessary  heating 
plant,  is  computed  with  inside  temperature  of  70° 
and  outside  temperature  of  20°  below  zero.  (90° 
Fahrenheit  temperature  difference.) 

In  figuring  coal  saving  7,200  B.  t.  u.  are  taken  as 
the  useful  heat  from  anthracite  coal,  per  pound,  as 
fired  under  average  conditions.  (Harding  a 
Willard.)  In  figuring  fuel  oil  or  gas  it  will  be 
necessary  to  calculate  the  consumption  on  the 


basis  of  the  efficiency  of  the  burner  and  on  the 
available  heat  in  these  fuels. 

Heat  losses  through  windows  and  heat  losses  due 
to  infiltration  are  assumed  to  be  the  same  where 
insulation  is  used  as  where  no  insulation  is  used. 
Heat  loss  due  to  infiltration  will  in  actual  practice 
vary,  depending  upon  the  wall,  and  window-  and 
door-frame  construction.  Calking  around  win¬ 
dows,  well  fitted  insulation,  beam  fills,  storm  sash 
and  weather  stripping  all  cut  down  air  infiltration. 
Houses  insulated  with  Flax-li-num  placed  between 
the  studding  let  through  less  air  than  if  no  such 
material  were  in  place.  For  this  reason  actual  in¬ 
sulated  houses  show  bigger  fuel  savings  than  those 
indicated  here.  Infiltration  is  a  variable  factor 
and  the  following  data  have  been  based  on  the  same 
infiltration  for  the  insulated  and  non-insulated 
house.  Infiltration  is  taken  as  N  equals  1.  That  is, 
one  complete  air  change  takes  place  in  the  house 
every  hour. 

Key  to  Syinhols  Used  in  the  Following 
Comyutations 

H  =  Total  heat  in  B.  t.  u.’s 
W  =  Wall  surface  in  square  feet 
G  =  Glass  surface  in  square  feet 
C  =  Ceiling  surface  in  square  feet 
V  =  Volume  of  air  in  cubic  feet 
N  =  No  air  changes  per  hour  (Infiltration) 

Ti  =  Room  temperature 
To  =  Outside  temperature 
Kw  =  Heat  transmission  constant  for  wall 
Kg  =  Heat  transmission  constant  for  glass 

Hw  =  Heat  in  B.  t.  u.  transmitted  through  wall  per  hour  or  KwW  (Ti — To) 
Hg  =  Heat  in  B.  t.  u.  transmitted  through  glass  per  hour  or  KgG  (Ti — To) 
Ha  =  Heat  in  B.  t.  u.  lost  by  infiltration  per  hour  or  .O^VN  (Ti — To) 

He  =  Heat  in  B.  t.  u.  transmitted  through  ceiling  per  hour  KeC  (Ti — To) 


Heat  Insulation  for  Houses 


19 


I 


I 

I 


FIR.ST  FLOOI^ 

CE-IUING  HEIGHT  a  4-' 


SECOND  FLOOR. 

CEILING  HE.IGHT  6'  O" 


Floor  Plans  and  Elevation  of  Two  Story  House 


Copyright  1924 — The  Architects’  Small  House  Service  Bureau — Home  Plan  No.  6A17 ,  Northwestern  Div.  Inc. 


20 


Heat  Insulation  for  Houses 


Radiation  and  Fuel  Savings  on  a  House 

(ARCHITECTS’  SMALL  HOUSE  SERVICE  BUREAU  PLAN  NUMBER  6A17  ON  PAGE  19.) 


\V  =  1872  Square  Feet  Wall  Surface  C  =  176  Sq.  Ft.  at  Roof  Constant  V  =  11,880  Cu.  Ft.  Volume 

G=211  Square  Feet  Glass  Surface  Cl  =  484  Sq.  Ft.  at  Eave  Line  Constant 


Stucco  Finished  Walls  (Page  14) 

A-l 

B-l 

C-l 

D-l 

E-l 

F-l 

Kw . 

.242 

.146 

.287 

.161 

.357  ! 

.181 

Kc . 

.45 

.45 

.45 

.45 

.45 

.45 

Kc . 

.179 

.104 

.179 

.104 

.179 

.104 

Kcl . 

.220 

.116 

.220 

.116 

.220 

.116 

IIw . 

40,772 

24,598 

48,354 

27,124 

60,147 

30,544 

lie . 

8.546 

8,546 

8,546 

8,546 

8,546 

8,546 

lie . 

2,835 

1,647 

2,835 

1,647 

2,835 

1,647 

IlCT . 

9,583 

5,053 

9.583 

5,053 

9,583 

5,053 

Hv . 

21.384 

21,384 

21,384 

21,384 

21,384 

21,384 

Total . 

83,120 

61,230 

90,702 

63,754 

102,495 

67,174 

10%  for  Exposure . 

8,312 

6,123 

9,070 

6,375 

10,250 

6,717 

Total  Loss  per  Hour . 

91,432 

67,353 

99,772 

70,129 

112,745 

73,891 

Total  Radiation  Required . 

610 

449 

665 

468 

752 

492 

Coal  in  Tons  per  Season . 

13.6 

9.9 

14.8 

10.2 

16.7 

10.7 

Brick  Finished  Walls  (Page  15) 

A-2 

B-2 

C-2 

D-2 

E-2 

F-2 

Kw . 

.210 

.153 

.255 

.141 

.191 

.146 

Kg . 

.45 

.45 

.45 

.45 

.45 

.45 

Kc . 

.179 

.104 

.179 

.104 

.179 

.104 

Kcl . 

.220 

.116 

.220 

.116 

.220 

.116 

Hw . 

35,381 

22,408 

42,962 

23,756 

32,179 

24,598 

Hg . 

8,546 

8,546 

8,546 

8,546 

8,546 

8,546 

lie . 

2,835 

1,647 

2,835 

1,647 

2,835 

1,647 

Hcl . 

9,583 

5,053 

9,583 

5,053 

9,583 

5,053 

Hv . 

21,384 

21,384 

21,384 

21,384 

21,384 

21,384 

Total . 

77.729 

59,038 

85,310 

60,386 

74,527 

61,228 

10%  for  Exposure . 

7,773 

5,904 

8,531 

6,039 

7,453 

6,123 

Total  Loss  per  Hour . 

85,502 

64,942 

93,841 

66,425 

81,980 

67,351 

Total  Radiation  Required . 

570 

433 

626 

443 

547 

449 

Coal  in  Tons  per  Season . 

12.6 

9.6 

13.8 

9.8 

12  1 

9.9 

Siding  Finished  Walls  (Page  16) 

A-3 

B-3 

C-3 

D-3 

E-3 

F-3 

Kw . 

.255 

.151 

.216 

.136 

.229 

.141 

Kg . 

.45 

.45 

.45 

.45 

.45 

.45 

Kc . 

.179 

.104 

.179 

.104 

.179 

.104 

Kcl . 

.220 

.116 

.220 

.116 

.116 

.116 

Hw . 

42,962 

25,440 

36,391 

23,072 

38,582 

23,756 

Hg . 

8,546 

8,546 

8,546 

8,546 

8,546 

8,546 

He . 

2,835 

1,647 

2,835 

1,647 

2,835 

1,647 

Hcl . 

9,583 

5,053 

9,583 

5,053 

9,583 

5,053 

Hv . 

21,384 

21,384 

21,384 

21,384 

21,384 

21,384 

Total . 

85,310 

62,070 

78,739 

59,702 

80,930 

60,386 

10%  for  Exposure . 

8,531 

6,207 

7,874 

5,970 

8,093 

6,039 

Total  Loss  per  Hour . 

93,841 

68,277 

86,613 

65,672 

89,023 

66,425 

Total  Radiation  Retjuired . 

629 

456 

577 

438 

594 

443 

Coal  in  Tons  per  Season . 

13.8 

10.0 

12.9 

9.6 

13.2 

9.8 

Heat  Insulation  for  Houses 


21 


Comparison  of  Required  Radiation  and  Fuel  Consumption 
m  H  ouses  Built  from  the  Same  Plan  with 
Common  Types  of  Walls  and  Roofs 

(ARCHITECTS’  SMALL  HOUSE  SERVICE  BUREAU  PLAN  NUMBER  6A17,  Page  19.) 


NON-INSULATED  HOUSE 

INSULATED  HOUSE 
(Identical,  except  for  Insulation) 

Wall 

Number 

Value  of  K 

Radiation 

Required 

Tons  of  Coal 
per  Season 

Wall 

Number 

Value  of  K 

Radiation 

Required 

Tons  of  Coal 
per  Season 

A-1 

.242 

610 

13.6 

B-1 

.146 

449 

9.9 

C-1 

.287 

665 

14.8 

D-1 

.161 

468 

10.2 

E-1 

.357 

752 

16.7 

F-1 

.181 

492 

10.7 

A-2 

.210 

570 

12.6 

B-2 

.133 

433 

9.6 

C-2 

.255 

626 

13.8 

D-2 

.141 

443 

9.8 

E-2 

.191 

547 

12.1 

F-2 

.146 

449 

9.9 

A-3 

.255 

629 

13.8 

B-3 

.151 

455 

10.0 

C-3 

.216 

577 

12.9 

D-3 

.136 

438 

9.6 

E-3 

.229 

594 

13.2 

F-3 

.141 

443 

9.8 

Average . 

.249 

619 

13.7 

.148 

452 

9.9 

Saving  thru  Ceiling  of  Above  House  .179 — .104  =41.9  Per  Cent 

.179 

Saving  thru  Average  Walls  .249 — .148  =40.6  Per  Cent 

.249 

Average  Saving  on  Radiation  619 — 452  =27.0  Per  Cent 

619 


Average  Saving  in  Fuel  per  Season  13.7 — 9.9  =27.8  Per  Cent 

13.7 


When  it  is  90  degrees  outside,  the  in¬ 
terior  of  the  /^/ax-Zi-ntim-insulated 
home  is  10  to  15  degrees  cooler. 


When  it  is  20  below  outside,  the  tem¬ 
perature  of  a  Flax-li-num-Ymed  home 
is  easily  maintained  at  70  degrees. 


22 


Heat  Insulation  for  Houses 


Heat  Losses  on  Bungalow  Type  Houses 


HE  more  compactly  a  house  is  designed  the  lower  will  be  the  fuel  bill  per 
cubic  foot  of  space.  Square  and  rectangular  houses  burn  less  fuel  than 
those  of  more  complex  design.  Fuel  bills  alone  do  not  govern  the  design 
of  houses.  It  is  advisable  however  to  take  cognizance  of  house  types  that 
increase  heat  losses  and  where  these  types  are  employed  to  reduce  the  losses  by  the 
proper  application  of  the  correct  building  insulation. 


One  of  the  most  common  of  the  high-heat-loss 
types  is  the  one-story  bungalow  and  its  modifica¬ 
tion,  the  story  and  a  half  house.  In  this  class  may 
be  included  all  houses  with  relatively  large  roof 
areas  and  without  attic  floors  or  finished  rooms 
above  the  first  floor.  This  includes  a  great  many 
houses  of  the  Dutch  Colonial  type  and  most 
houses  of  the  smaller  English  Cottage  type. 

One  cause  for  the  higher  heat  loss  in  this  house- 
type  lies  in  the  construction  of  the  roof  and  ceiling. 

Where  the  roof  and  ceiling  combination  of  the 
two-story  house  (pages  20  and  21),  including  the 
attic  floor,  without  heat  insulation  is  .179  B.  t.  u., 
the  roof  of  the  one-story  and  Dutch  Colonial  types 
(pages  24  and  25)  is  .284  B.  t.  u.  (See  Roofs  A 
and  C.  Page  17.)  The  relation  between  these 
two  roof  types  is  as  follows: 


with  1  X  2’s  to  receive  lath  and  j^laster  cuts  the 
transmission  from  .284  to  .132  B.  t.  u.  This  es¬ 
tablishes  the  relation  between  the  insulated  and 
uninsulated  roof  as  follows: 

Saving  in  heat 
transmission  thru 
ceiling  and  roof 
combination. 

(One-Story  Bungalow) 

This  saving  of  50.3  percent  is  to  be  compared 
with  the  following  saving  made  by  insulating  the 
roof  of  the  full  two-story  house: 

Saving  in  heaC 
transmission  thru 
ceiling  and  roof  com¬ 
bination. 

(Two-Story  House) 


.284  — .132 

-  =-■  50.3% 

.284 


.179  — .104 
- -  12% 

.179 


Difference  in  heat 
transmission  thru 
roof  of  bungalow  and 
two-story  house. 


.284  — .179 

-  =  37% 

.284 


This  percentage  is  somewhat  reduced  by  the  cor¬ 
rection  made  on  the  two-story  type  for  convection 
around  the  attic  floor  at  the  eave  line.  In  a  great 
manv  houses  much  of  the  benefit  of  the  attic  floor 

t. 

is  lost  by  poor  construction  at  that  point. 

If  tlie  heat  loss  through  bungalow  roofs  is  higli, 
great  reductions  can  l)e  made  by  properly  heat  in¬ 
sulating  these  roofs.  One  inch  Flax-li-num  applied 
to  the  under  side  of  the  ceiling  joists  and  furred  out 


It  will  be  seen  from  the  above  that  the  unit  loss 
per  square  foot  of  roof  area  is  greater  in  the  one- 
story  house.  And  since  there  is  usually  a  larger 
proportional  roof  area  on  this  type  of  house  the 
total  heat  losses  are  noticeably  larger.  The  need 
for  heat  insulation  is  therefore  greater  and  the  sav¬ 
ings  made  by  heat  insulation,  are  larger  than  on 
the  two-story  types. 

To  illustrate  the  savings  made  by  heat  insulating 
houses  of  this  type  a  simple  one-story  bungalow  is 
figured  in  the  same  way  as  the  two-story  house. 
Like  the  two-story  type  this  home  is  shown  with 
all  applicable  wall  constructions. 


Heat  Insulation  for  Houses 


23 


24 


Heat  Insulation  for  Houses 


Radiation  and  Fuel  Savings  on  a  House 

(ONE  STORY  BUNGALOW  ON  PAGE  23.) 

W  =  1005  Square  Feet  Wall  Surface 

C  =  1060  Square  Feet  of  Ceiling  Surface 

G  =  162  Square  Feet  Glass  Surface 

V  =  9010  Cubic  Feet  Volume 

Stucco  Finished  Wall  Number  (Page  14) 

A-l 

B-1 

C-l 

D-l  , 

E-l 

F-l 

Kw . 

.242 

.146 

.287 

.161 

.357 

.181 

K(; . 

.45 

.45 

.45 

.45 

.45 

.45 

Kc . 

.284 

.132 

.284 

.132 

.284 

.132 

Hw . 

21,889 

13,206 

25,959 

14,562 

32.291 

16,375 

Hg . 

6,561 

6,561 

6.561 

6,561 

6,561 

6,561 

He . 

27,093 

12,593 

27,093 

12.593 

27,093 

12,593 

Hv . 

16,218 

16,218 

16,218 

16,218 

16,218 

16,218 

Total . 

71,761 

48,578 

75,831 

49,934 

82,163 

51,747 

10%  for  Exposure . 

7.176 

4,858 

7.583 

4,993 

8,216 

5,175 

Total  Loss  per  Hour . 

78,937 

53,436 

83,414 

54,927 

90,379 

56,922 

Total  Uadiation  Required . 

526 

356 

556 

367 

603 

379 

Coal  in  Tons  per  Season . 

11.7 

7.9 

12.3 

8.1 

13.3 

8.4 

Brick  Finished  Wall  Number  (Page  15) 

A-2 

B-2 

C-2 

D-2 

E-2 

F-2 

Kw . 

.210 

.133 

.255 

.141 

.191 

.146 

Kg . 

.45 

.45 

.45 

.45 

.45 

.45 

Kc . 

.284 

.132 

.284 

.132 

.284 

.132 

Hw . 

19,805 

11,830 

23,065 

12,753 

17,276 

13,206 

Hg . 

6,561 

6,561 

6,561 

6,561 

6,561 

6,561 

He . 

27,093 

12,593 

27,093 

12,593 

27,093 

12,593 

Hv . 

16,218 

16,218 

16,218 

16,218 

16,218 

16,218 

Total . 

69,677 

47,202 

72,937 

48,125 

67,148 

48,578 

10%  for  Exposure . 

6,968 

4,720 

7.294 

4,812 

6,715 

4,859 

Total  Loss  per  Hour . 

76,645 

51,922 

80,231 

52,937 

73,863 

53,437 

Total  Radiation  Required . 

512 

346 

535 

353 

493 

356 

Coal  in  Tons  jier  Season . 

11.3 

7.0 

11.8 

7.8 

11.0 

7.9 

Siding  Finished  Wall  Number  (Page  16) 

A-3 

B-3 

C-3 

D-3 

E-3 

F-3 

Kw . 

.255 

.151 

.216 

.136 

.229 

.141 

Kg . 

.45 

.45 

.45 

.45 

.45 

.45 

Ke . 

.284 

.132 

.284 

.132 

.284 

.132 

Hw . 

23,065 

13,658 

19,537 

12,282 

20,713 

12,753 

Hg 

6,561 

6,561 

6,561 

6,561 

6,561 

6,561 

He . 

27,093 

12,593 

27,093 

12,593 

27,093 

12,593 

Hv . 

16,218 

16,218 

16,218 

16,218 

16,218 

16,218 

Total . 

72,937 

49,029 

69,409 

47,654 

70.584 

48,125 

10^  for  Ex])osure . 

7,294 

4,903 

6,941 

4,765 

7,059 

4,812 

Total  Loss  ])er  Hour . 

80,231 

53,932 

76,359 

52,419 

77,643 

52,937 

Total  Radiation  Retjuired . 

535 

360 

509 

349 

518 

353 

Coal  in  Tons  jier  Season . 

11.9 

8.0 

11.3 

7.7 

11.5 

7.8 

Heat  Insulation  for  Houses 


25 


Comparison  of  Required  Radiation  and  Fuel  Consumption  in 
Houses  Built  from  the  Same  Plan  with  Common 

Types  of  Walls  and  Roofs 

(ONE  STORY  BUNGALOW,  PAGE  23) 


NON-INSULATED  HOUSE  INSULATED  HOUSE 


Wall 

Number 

Value  of  K 

Radiation 

Required 

Tons  of  Coal 
per  Season 

Wall 

Number 

Value  of  K 

Radiation 

Required 

Tons  of  Coal 
per  Season 

A-1 

.242 

526 

11.7 

B-1 

.146 

356 

7.9 

C-1 

.287 

556 

12.3 

D-1 

.161 

367 

8.1 

E-1 

.357 

603 

13.3 

F-1 

.181 

379 

8.4 

A-2 

.210 

512 

11.3 

B-2 

.133 

346 

7.0 

C-2 

.255 

535 

11.8 

D-2 

.141 

353 

7.8 

E-2 

.191 

493 

11.0 

F-2 

.146 

356 

7.9 

A-3 

.255 

535 

11.9 

B-3 

.151 

360 

8.0 

C-3 

.216 

509 

11.3 

D-3 

.136 

349 

7.7 

E-3 

.226 

518 

11.5 

F-3 

.141 

353 

7.8 

Average . 

.248 

532 

11.8 

.... 

.148 

358 

7.8 

Saving  thru  Ceiling  of  Above  House  .284 — .132  =53.5  Per  Cent 

.284 

Saving  thru  Average  Insulated  Walls  .248 — .148  =40  Per  Cent 

.248 


Saving  in  Radiation,  average  532 — 358  =32.7  Per  Cent 

532 

Average,  Saving  in  Fuel  per  Season  11.8 — 7.8  =33.9  Per  Cent 

11.8 


The  pioneer  New  Englanders  filled  the 
hollow  walls  of  their  log  cabins  with 
grass  and  straw  bound  together  with 
mud. — Primitive  Insulation. 


The  occupants  of  a  Flax-li-num- 
lined  house  are  completely  enclosed 
by  a  heat-resisting  material  that  keeps 
the  heat  in  during  the  winter  and  out 
during  the  summer. 


26 


Heat  Insulation  for  Houses 


'  T  I  1  51  ■'  L  CC  H  P  I  4  M  ' 

'  i.  .  *•  -c.' 


5lC  ON  D  [LOOL  flAN' 
s  c  »  L  t  i,  •  I -o‘ 


Floor  Plans  and  Elevation  of  a  Larger  House 


Heat  Insulation  for  Houses 


27 


Comparison  of  Required  Radiation  and 
Fuel  Consumption  in  a  Larger  House 

SEE  FRONTISPIECE  (PAGE  2)  AND  PAGE  26 


W  =3135  Square  Feet  Wall  Surface  C  =  2637  Square  Feet  of  Ceiling  Surface 

G  =598  Square  Feet  Glass  Surface  V  =  36080  Cubic  Feet  Volume 


Wall  Number 

Ceiling  Number 

A-2 

C-1 

B-2 

D-1 

Kw . 

.210 

.133 

Kc . 

.284 

.132 

Kg . 

.45 

.45 

Hw . 

59,252 

36,526 

He . 

67,302 

31,328 

Hg . 

24,219 

24,219 

Hv . 

64,944 

64,944 

Total . 

215,717 

158,017 

10%  for  Exposure . 

21,572 

15,802 

Maximum  Loss  per  Hour . 

237,289 

173,819 

Total  Rad.  Req.,  Hot  Water . 

1,582 

1,159 

Total  Rad.  Req.,  Vapor . 

989 

724 

Coal  in  Tons  per  Season . 

35.0 

25.6 

Saving  thru  Ceiling  of  Above  House  .284 — .132  =53.6  Per  Cent 

.284 


Saving  thru  Wall  .210 — .133  =36.8  Per  Cent 

^210 

Saving  in  Radiation  1582 — 1159  =26.7  Per  Cent 

1582 

Saving  in  Fuel  per  Season  35.0 — 25.6  =26.7  Per  Cent 

35.0 


Note — To  simplify  computations  all  walls  have  been  taken  as  brick  veneer,  although  small  parts  of 
the  top  story  are  actually  stucco  and  half  timber. 


It  requires  less  fuel  to  properly  heat  a 
F la x-li-num -lined  house.  Fuel  bills 
average  30%  less  where  Flax-U-num 
is  used. 


Flax-li-num  has  been  tested  and 
proved  in  thousands  of  buildings  in 
every  section  of  the  country  for  more 
than  seventeen  years. 


28 


Heat  Insulation  for  Houses 


Suggestions  for  Specifying  Heat 

Insulation 


\' ERY  Flax-li-num  specification  is  designed  to  take  advantage  of  scientific 
principles — to  give  the  greatest  return  at  the  most  reasonable  cost.  The 
experience  of  a  seasoned  organization  of  highly  trained  engineers,  plus  sev¬ 
enteen  years  of  actual  use  in  thousands  of  homes  and  industrial  jobs,  form 
the  sound  basis  for  Flax-li-num  specifications. 

There  are  four  things  to  cover  in  specifying  Heat  Insulation.  The  wording  may 


vary,  but  unless  the  following  points  are  plainly 
covered,  the  client  is  not  likely  to  secure  the  full 
benefit  from  his  insulation. 

1.  Placing  or  Application 

Specify  the  exact  places  where  insulation  is  to  go. 
The  effectiveness  of  heat  insulation  is  increased  if 
applied  between  studdings,  midway  between  the 
sheathing  and  lath  and  plaster  on  frame  con¬ 
struction,  or  furred  out  on  masonry  construction. 
Effectiveness  is  increased  when  heat  insnlation 
goes  bet 01V  top  story  ceiling  joists  instead  of  over 
them  or  on  the  rafters.  Effectiveness  is  decreased 

by  applying  insulation  out¬ 
side  of  sheathing,  or  by 
using  as  a  plaster  base. 
Elax-li-num  should  be  ap- 
l)lied  as  shown  here;  the 
]/2'  hanged  material  as  de¬ 
scribed  above ;  the  one-inch 
material  below  top  story 
ceiling  joists,  with  the 
sheets  paralleling  the  joists. 

Elax-li  -nuni  for  ceiling 
insulation  is  made  32" 
wide  so  as  to  make  all 
edges  come  directh^  below  ceiling  joists  set  16  inches 
on  centers.  The  hanged  material  is  and 

24)^"  wide,  made  to  ht  between  studs  spaced  16 
or  24  inches  on  centers. 


Applying  Half-Inch  Flanged 
Flax-li-num  in  frame  walls 
Quick,  easy  and  efficient 


2.  Thickness  of 
Material 

Laboratories,  in  their 
reports,  give  the  transmis¬ 
sion  of  insulating  materials 
on  the  basis  of  one  inch  of 
thickness.  Most  materials 
as  actually  sold  are  only 
a  fraction  of  that  thick¬ 
ness,  thus  necessitating  the 
computation  of  transmis¬ 
sion  coefficient  for  the 
thickness  furnished.  The 
benehts  of  true  heat  insula¬ 
tion  come  where  at  least  one-half  inch  of  Elax-li-num 
is  used  in  walls  in  addition  to  all  other  standard 
parts  of  the  wall,  such  as  sheathing,  lath,  building 
paper,  etc.  In  roofs,  where  the  greatest  heat  losses 
occur,  true  heat  insulation  means  Elax-li-num  one 
inch  thick. 

2.  Raw  Material  and  Form 

xMter  trials  and  tests  upon  many  raw  materials 
and  ev ery  form  of  insulation,  the  makers  of  Elax-li- 
num  settled  upon  purified  flax  and  semi-rigid  board 
form,  as  the  most  efficient  and  practical. 

Elax-li-num  is  pure  flax.  There  is  no  other 
material  used  in  its  manufacture.  It  is  felted 
together;  there  is  no  “binder”  or  foreign  substance 
that  might  vary  in  strength  or  lose  its  efficiency  in 
the  course  of  years. 

Elax  fibre  is  the  basis  for  linen,  the  oldest  and 


Most  efficient  way  to  apply  Roof  In¬ 
sulation.  One-Inch  Flax-li-num  on 
under  side  of  top  story 
ceiling  joists 


Heat  Insulation  for  Houses 


29 


most  durahle  of  fa])rics.  In  the  form  of  “Tow” 
it  fills  most  of  our  ii])holstered  furniture.  These 
uses  indicate  the  durability  and  long  life  of  the  raw 
material.  Flax-li-iium  has  been  taken  out  of  Rail¬ 
road  Refrigerator  Cars  after  fifteen  years  of  service 
in  such  good  condition  that  it  was  used  again  in 
the  rebuilt  cars.  This  has  occurred  not  in  single 


This  is  One-Inch  Flax-li-nitm. 
Insvlation  for  House  Roofs  should  be  this  thick. 


instances,  but  in  whole  series  of  cars  numbering 
into  the  thousands. 

The  semi-rigid  form  was  chosen  as  giving  the 
highest  insulating  efficiency  combined  with  dura¬ 
bility,  ease  of  application  and  long  life,  thus  making 
it  a  practical  building  material. 

Flax-li-num  is  flexible  enough  to  fit  around  un¬ 
even  places  and  to  make  tight  joints  with  studdings, 
joists  or  rafters.  It  takes  up  shrinkage  of  timbers 
and  settlement  of  buildings  without  tearing  or 
pulling  away.  It  cannot  warp  or  buckle.  Yet  it 
is  not  flimsy.  Workmen  can  handle  it  without 
the  extreme  care  that  slows  up  construction.  It 
does  not  tear  or  puncture.  The  petty  accidents 
of  construction  leave  its  efficiency  unimpaired. 
And  it  is  guaranteed  to  stay  in  place,  at  fidl  effi¬ 
ciency,  as  long  as  the  building  stands. 

Workmanship 

Correct  and  workmanlike  application  is  as  es¬ 
sential  in  insulation  as  in  any  other  detail  of  con¬ 
struction.  It  is  necessary  that  the  contractor  be 


furnished  with  a  definite  specification  which  will 
take  care  of  important  details,  and  that  this  spec¬ 
ification  be  followed  in  an  intelligent  manner,  with 
a  view  to  the  results  which  are  expected.  All 
window  and  door  frames  should  be  thoroughly 
calked  with  scrap  pieces  of  Flax-li-num.  A  con¬ 
scientious  builder,  by  careful  work  around  the 
windows,  by  notching  and  flanging  Flax-li-mim 
sheets  at  the  top  and  bottom  and  by  seeing  that 
sheets  of  such  length  are  used  that  the  insulation 
may  be  a  continuous  sheet  from  plate  to  plate,  can 
increase  greatly  the  comfort  of  the  insnlated  home. 

We  recommend  as  a  heat  saver  the  double 
window  casing,  and  further  recommend  the  beam 
fill  as  a  barrier  to  the  entrance  of  heat  and  cold  at 
the  foundation  line. 

The  principal  reason  for  headers  at  the  ceiling 
line  in  gables  is  to  provide  a  heat  stop  and  a  nailing 
base  for  the  top  of  Flax-li-num  sheets  at  that  point. 


LIST  OF  FLAX-LI-NUM  SPECIFICATIONS 


4- A.  Insulation  for  a  storv-and-a-half 

semi-bungalow  ---------  Page  31 

13- A.  Insulation  for  a  one  or  two  storv 

house  -------------  Page  33 

8-x4.  Insulation  for  brick  veneer  houses 

or  two  flats  -  --  --  --  --  -  Page  35 
ll-A.  Flax-li-num  Keyboard — heat  insu¬ 
lation  and  plaster  base  for  brick 
and  hollow  tile  houses,  bungalows 
or  two  flats  -  --  --  --  --  -  Page  37 
3-A.  Sound  Control — side  wall  and  roof 
insulation,  where  studding  is  brok¬ 
en  at  ceiling  line  -------  Page  43 

7-A.  Sound  Control — side  wall  and  roof 
insulation,  where  studding  is  not 
broken  at  ceiling  line  -----  Page  45 

5- A.  Sound  Control  and  roof  insulation 

where  outside  walls  are  of  brick  or 
hollow  tile  -  --  --  --  --  -  Page  47 
2-A.  Heat  insulation  for  flat  roof  decks 

of  concrete  or  wood  ------  Page  55 

14- x4.  Heat  insulation  for  steel  deck  roofs  Page  57 


30 


Heat  Insulation  for  Houses 


^  ft  JS/r 

••^. 

e»0!// fog  <A  '  .-f  c- »' 

*  «^>.s  «'■-.'  s  /.f ,  .^FTTfow/'Mm 

A%7;. 

:■  •  'i'  .::fo.:m^^ 

fe*  A/i  ''^,:f:  'fo^^^yi^//'t 


Header 

Important 


Calk  Window 
Frames  and 
Door  Jambs 
Thoroughly  with 
Scrap  Pieces 
of  Flax-li-num 


^0m 


Siding~^ 

Paper 

Sheathing 


Yl'  Flanged  for 
Wall  Insulation 


Air  Space 

Lath 

Plaster 


Studding  Flax-li-num 


r 

F 

Heat  Insulation  for  Houses  31 


Insulation  for  a  Story  and  One-Half  Semi-Bungalow 

Standard  Specification  No.  4-A 

[As  Per  Detail  on  Opposite  Page] 

SIDE  WALL  INSULATION 

(1)  Materials:  Heat  Insulation  for  all  outside  walls  shall  be  3^" 
Flanged  Flax-li-num,  manufaetured  by  the  Flax-li-nnm  Insulat¬ 
ing  Company,  St.  Paul,  Minn. 

(2)  Application:  Flanged  Flax-li-num  sheets  shall  be  applied  be¬ 

tween  studdings  from  lower  to  top  plate.  Top  and  bottom  of 
sheets  shall  be  notched  and  flanged  into  place.  Binding  strips 
(lath)  shall  be  securely  nailed  through  flanged  edges  and  top  and 
bottom  of  Flax-li-num  sheets  to  studdings  and  plates  (to  insure 
tight  joints).  In  gables,  blocks  of  studding  dimension  shall  be 
inserted  between  studding  flush  with  bottom  edge  of  ceiling  joists. 
Insulation  shall  be  run  to  these  headers  and  fastened  to  them 
with  lath.  (Detail  on  opposite  page.) 

ROOF  INSULATION 

(3)  Materials:  Heat  Insulation  for  the  roof  shall  be  1''  Flax-li-num 
flat  sheets,  manufactured  by  the  Flax-li-num  Insulating  Company, 

St.  Paul,  Minn. 

(4)  Application:  1"  Flax-li-num  Flat  Sheets  shall  be  applied  to  the 
under  side  of  rafters  and  collar  beams.  At  intersection  of  rafters 
and  collar  beams  wood  headers  shall  be  placed  between  rafters 
and  insulation  fastened  to  these  headers  (to  provide  tight  joints). 
Insulation  shall  be  furred  out  with  1  x  2’s  over  rafters  and  collar 
beams  to  receive  lath  and  plaster.  At  all  end  joints  of  insulation 
insert  wood  headers  and  nail  both  sheets  to  these  headers  to 
insure  tight  joints. 


32 


Heat  Insulation  for  Houses 


1"  on  Ceiling 
for  Roof  Insulation 


Header 

Important 


Siding 
Sheathing 
Flax-li-num 
Lath  86  Plaster 


Calk  Window 
Frames  and 
Door  Jambs 
Thoroughly  with 
Scrap  Pieces 
of  Flax-li-num 


34  Flanged  for 
Wall  Insulation 


t  %.  t 


-Vi 

k  ^  ~  >  V.  e 


»  V'f;? 
■»# 


Heat  Insulation  for  Houses 


33 


Insulation  for  a  One-  or  Two-Story  House 

Standard  Specification  No.  13-A 

[As  Per  Detail  on  Opposite  Page] 

SIDE  WALL  INSULATION 

(1)  Materials:  Heat  Insulation  for  all  outside  walls  shall  be  3^" 
Flanged  Flax-li-num,  manufactured  by  the  Flax-li-num  Insulat¬ 
ing  Company,  St.  Paul,  Minn. 

(2)  Application:  Flanged  Flax-li-num  sheets  shall  be  applied  be¬ 

tween  studding  from  lower  to  top  plate.  Top  and  bottom  of 
sheets  shall  be  notched  and  flanged  into  place.  Binding  strips 
(lath)  shall  be  securely  nailed  through  flanged  edges  and  top  and 
bottom  of  Flax-li-num  sheets  to  studdings  and  plates  (to  insure 
tight  joints).  In  gables,  blocks  of  studding  dimension  shall  be 
inserted  between  studding  flush  with  bottom  edge  of  ceiling 
joists.  Insulation  shall  be  run  to  these  headers  and  fastened  to 
them  with  lath.  (See  detail  opposite.) 

ROOF  INSULATION 

(3)  Materials:  Heat  Insulation  for  the  roof  shall  be  1"  Flax-li-num 
flat  sheets,  manufactured  by  the  Flax-li-num  Insulating  Company, 
St.  Paul,  Minn. 

(4)  Applicatiori:  1"  Flax-li-num  flat  sheets  shall  be  applied  to  the 
under  side  of  top  floor  ceiling  joists.  Insulation  shall  be  furred 
out  with  1  X  2’s  under  joists  to  receive  lath  and  plaster.  At  all 
end  joints  of  Flax-li-num  insert  wood  headers  and  nail  both  sheets 
to  these  headers  to  insure  tight  joints. 


34  Heat  Insulation  for  Houses 


Heat  Insulation  for  Houses 


35 


Heat  Insulation  for  Brick  Veneer  Houses 

Standard  Specification  No.  8-A 

[As  Per  Detail  on  Opposite  Page] 

HEAT  INSULATION  FOR  WALLS 

(1)  Materials:  Heat  Insulation  for  outside  walls  shall  be  3^"  Flanged 
Flax-li-num,  manufactured  by  the  Flax-li-nuin  Insulating  Com¬ 
pany,  St.  Paul,  Minn. 

(2)  Application:  Y2'  Flanged  Flax-li-num  sheets  shall  be  applied 
between  studding  from  lower  to  top  plate.  Top  and  bottom  of 
sheets  shall  be  notched  and  flanged  into  place.  Binding  strips 
(lath)  shall  be  securely  nailed  through  flanged  edges  and  top  and 
bottom  of  Flax-li-num  sheets  to  studdings  and  plates  (to  insure 
tight  joints).  In  gables,  blocks  of  stud  dimension  shall  be  in¬ 
serted  between  studding  flush  with  bottom  edge  of  ceiling  joists. 
Insulation  shall  be  run  to  these  headers  and  fastened  to  them 
with  lath.  On  outside  of  sheathing  apply  building  paper  and  lay 
up  brick  in  regular  manner. 

ROOF  INSULATION 

(3)  Materials:  Heat  insulation  for  the  ceiling  of  the  top  story  shall 
be  1"  Flax-li-num  flat  sheets,  manufactured  by  the  Flax-li-num 
Insulating  Company,  St.  Paul,  Minn. 

(4)  Application:  1"  Flax-li-num  flat  sheets  shall  be  applied  to  the 
under  side  of  top  floor  ceiling  joists.  Insulation  shall  be  furred 
out  with  lx2’s  under  joists  to  receive  lath  and  plaster.  At  all 
end  joints  of  Flax-li-num  insert  wood  headers  and  nail  both 
sheets  to  these  headers  to  insure  air  tight  joints. 


36 


Heat  Insulation  for  Houses 


Heat  Insulation  for  Houses 


Heat  Insulation  for  Brick  and  Hollow  Tile  Houses 

or  Bungalows 

Standard  Specification  No.  11-A 

[As  Per  Detail  on  Opposite  Page] 


HEAT  INSULATION  FOR  WALLS 

(1)  Materials:  Heat  insulation  for  all  outside  walls  shall  be  Flax-li-num  Keyboard 
manufactured  by  the  Flax-li-num  Insulating  Company,  St.  Paul,  IVIinn. 

(*2)  Millwork:  Window  and  door  frames  shall  be  made  to  aceommodate  thickness 
of  wall  plus  furring  strips  plus  3^"  extra  thickness  for  Keyboard. 

(3)  Application:  In  laying  tile  walls  insert  lath  horizontally  into  mortar  joints 
every  two  feet.  To  these  lath  nail  1x2  furring  stri])s  vertically,  on  16" 
centers.  x4pply  Flax-li-num  Keyboard,  breaking  vertical  joints  every  3  feet. 
Nail  each  lath  on  Keyboard  into  every  furring  strip  with  6d  nail.  Apply 
plaster  in  usual  manner,  covering  lath  to  a  depth  of  ^  inch. 

between  first  and  second  floors  insert  small  pieces  of  Keyboard  or  flanged 
Flax-li-num  between  joists  to  properly  insulate  this  space. 

ROOF  INSULATION 

(4)  Materials:  Heat  insulation  for  the  roof  shall  be  1"  Flax-li-num  flat  sheets, 
manufactured  by  the  Flax-li-num  Insulating  Company,  St.  Paul,  Minn. 

(5)  Application:  1"  Flax-li-num  flat  sheets  shall  be  applied  to  the  under  side 
of  top  story  ceiling  joists.  Insulation  shall  be  furred  out  with  1  x  2"  under 
joists  to  receive  lath  and  plaster.  At  all  end  joints  of  Flax-li-num  insert 
wood  headers  and  nail  both  sheets  to  these  headers  to  secure  tight  joints. 

Flax-li-num  Keyboard — A  Plaster  and  Stuceo  Base 
that  Really  Insulates 

The  use  of  Flax-li-num  Keyboard  offers  many  advantages  to  the  man  who  plans 
to  build  a  stucco  house,  or  one  of  masonry  construction,  that  are  not  found  in  the 
ordinary  plaster  and  stucco  base  and  the  ordinary  insulating  material. 

Flax-li-num  Keyboard  is  a  combination  of  a  correct  insulating  material  and  a 
time-tried  and  proved  meehanieal-key  base  for  plaster  or  stucco. 

Flax-li-num  Keyboard  is  made  up  of  one-half  inch  Flax-li-num,  a  thick  sheet  of 
waterproof,  asphalt  saturated  paper  and  No.  1  pine  beveled  or  dove-tailed  wood  lath. 

The  use  of  best  cpiality  lath  insures  a  positive  mechanical  key  between  ])laster 
or  stucco  and  Flax-li-num  Keyboard,  and  forms  a  base  which  holds  the  plaster  or 
stucco  permanently  without  danger  of  unsightly  cracking  or  falling  off. 


38 


Heat  Insulation  for  Houses 


Flax-li-num  Sound  Control 


HE  I’apid  increase  in  late  years  of  the  number  of  apartments,  the  coming  of 
the  one  and  two  room  “kitchenette”  apartment  and  the  great  increase  in 
the  number  of  families  housed  per  apartment  building  which  resulted  there¬ 
from,  has  forced  the  science  of  sound  control  to  the  attention  of  archi¬ 
tects  and  engineers  everywhere.  Good  sound  control,  the  cutting  off  of  sound  trans¬ 
mission  between  different  portions  of  the  same  structure,  has  always  been  a  desirable 


((iiality.  It  has  been  sought  after  more  or  less 
by  designers  of  hotels,  hospitals  and  apartments. 
But  the  problems  in  years  past  were  never  so  acute 
as  those  encountered  by  the  architect  of  today. 
The  apartments  of  yesterday  usually  had  high 
ceilings  and  there  were  seldom  more  than  two  to 
a  floor.  There  were  fewer  families  per  building 
and  thus  fewer  people  using  party  hallways,  less 
concentration  into  one  or  two  rooms,  more  space 
per  family.  All  these  things  made  less  necessary 
the  scientific  control  of  sound  which  is  so  essential 
in  apartments  today. 

The  Moderri  Apartment 

The  modern  apartment  presents  a  different  prob¬ 
lem.  When  2.5  to  200  families  occupy  jointly  a 
single  l)uilding,  it  becomes  highly  essential,  if 
privacy  is  to  be  maintained  to  any  extent,  that 
party  walls,  floors  and  ceilings  be  rendered  as  sound 
l)roof  as  is  humanly  possible.  This  is  especially 
desiral)le  in  view  of  the  class  of  tenants  usually 
sought  after  for  the  elaborate  modern  apartment 
l)uildings.  It  cannot  be  expected  that  the  homes 
of  people  of  refinement  should  be  subjected  to  the 
constant  annoyance  of  their  neighbor’s  Radio,  to 
the  sound  of  walking  about  in  the  halls  and  of  con¬ 
versations  in  the  adjoining  apartments,  nor  that 
their  own  conversations  should  be  overheard  bv 
their  neighbors  to  the  right  or  left  of  them.  If  the 
modern  apartment  is  to  permanently  fill  the  j)lace 
it  seems  to  have  taken  in  the  life  of  American  cities, 
it  must  l^e  made  to  correspond,  as  nearly  as  possible 
to  the  private  home.  In  other  words,  })rivacy 
must  be  built  into  the  structure,  and  it  is  just  as 
essential  that  this  ])rivacy  be  maintained  as  it  is 


that  the  heating  plant  be  adequate  and  that  the 
service  be  up  to  standard.  Without  privacy,  the 
modern  apartment  can  never  be  more  than  a  tem¬ 
porary  dwelling  place,  to  be  endured  only  until  bet¬ 
ter  quarters  are  available.  Privacy  is  more  neces¬ 
sary  than  expensive  finish,  more  vital  than  fixtures, 
built-in  features  or  service. 

Owners  are  beginning  to  realize  these  facts,  and 
they  will  be  brought  home  more  and  more  force¬ 
fully  within  the  next  few  years.  The  real  test  of 
the  apartment  will  come  when  home-building  is 
resumed  on  an  extensive  scale,  when  competition 
shall  exist  between  the  apartment  and  the  private 
home.  If  the  investments  that  apartment  owners 
are  making  today  are  to  be  permanently  lucrative, 
the  apartment  will  have  to  offer  more  than  mere 
living  quarters.  Arrangement  cannot  compensate 
for  loss  of  privacy.  Convenience  is  but  a  matter 
of  design.  These  obvious  advantages  must  be 
combined  with  privacy  secured  through  proper 
sound  control. 

Principles  of  Sound 

Sound,  like  heat,  is  not  a  substance,  but  a  vi¬ 
bration.  Sound  varies  with  the  velocity  and  wave 
length  of  the  vibration,  differing  vibrations  pro¬ 
ducing  different  tones,  and  various  materials  in 
reflecting  and  magnifying  sound  also  produce  vari¬ 
ances  of  tone  quality.  The  vibrations  of  a  column 
of  air  differ  from  those  of  a  reed,  or  a  string.  These 
principles  govern  the  fashioning  of  all  musical 
instruments.  Sounds  which  combine  a  great  num¬ 
ber  of  tone  qualities,  which  are  by  far  the  most 
common,  are  simply  known  as  noise,  and  it  is  this 


Heat  Insulation  for  Houses 


39 


class  of  sound  which  makes  necessary  the  proper 
treatment  of  party  walls  and  floors  in  apartments, 
schools,  hotels  and  hospitals. 

Sound  vibrations  are  governed  b}"  the  substance 
in  which  they  are  set  u})  and  the  substances  through 
which  they  travel.  Thus,  some  substances  are 
better  conductors  of  sound  than  others.  More¬ 
over,  the  ease  with  which  sound  may  be  trans¬ 
mitted  from  one  point  to  another  is  proportional 
to  the  amount  of  resistance  to  the  vibrations  mak¬ 
ing  up  that  sound.  Thus,  if  a  sound  generated  on 
a  wood  floor  can  travel  along  the  joists,  through  the 
plate  and  into  the  studdings  below,  without  ever 
leaving  the  wood,  there  has  been  practically  no  re¬ 
sistance  to  its  passage.  The  same  principle,  ap¬ 
plied  to  a  column  of  air,  makes  possible  the  speak¬ 
ing  tube.  The  length  of  the  space  to  be  traveled 
is  relatively  unimportant. 

The  Susp ended  Ceiling 

The  above  explanation  makes  clear,  the  futility 
of  the  common  type  of  suspended  ceiling  as  a  bar¬ 
rier  to  sound  transmission.  Direct  contact  be¬ 
tween  floor  and  ceiling  has  been  cut  off,  but  sounds 
set  up  in  the  wood  of  the  floor  above  can  travel 
without  hindrance,  through  the  joists,  above  plates 
and  along  the  joists  laid  below.  There  is  a  con¬ 
tinuous  wooden  transmitter  for  the  sound. 

CoiTect  Sound  Control 

To  correctly  control  sound  between  floors,  it  is 
necessarv  to  cut  one  floor  off  from  the  other  with 

t/ 

some  non-conductor  of  sound.  To  place  a  laj^er  of 
sound  absorbing  material  between  rough  and  fin¬ 
ished  floor  helps  some,  of  course,  but  there  is  still 
a  continuous  transmission  through  the  studdings, 
plates  and  joists.  This  transmission  must  be 
broken  up,  or  a  satisfactory  job  cannot  be  secured. 

How  Sound  Is  Dissipated 

Sound  carried  to  a  material  is  broken  up  and 
dissipated  in  three  ways:  reflected;  transmitted; 


absorbed.  Therefore,  it  is  possible  that  while  a 
material  mav  l)e  extrenielv  low  in  transmission,  it 
may  be  very  high  in  reflection,  eliminating  it  as  an 
efficient  sound  controller.  The  test  is  in  the  ab- 
sorbing  (piality,  coupled,  of  course,  with  those 
qualities  which  are  inherent  in  every  good  building 
material — strength,  durability  and  ease  of  a])])li- 
cation. 


Specifying  Sound  Control 

In  specifying  sound  insulation,  there  are  four 
factors  upon  which  the  success  or  failure  of  the 
specification  depends.  1st:  the  sound  absorbing 
qualities  of  the  insulation;  2nd:  the  strength, 
durability  and  ease  of  application  of  the  material; 
3rd:  the  manner  in  which  the  insulation  is  ap¬ 
plied;  4th:  the  absence  of  any  other  conductor 
of  sound.  In  explanation  of  this  fourth  point,  if, 
after  the  controlling  system  has  been  carefully 
worked  out,  a  ventilating  flue  or  some  other  duct 
were  to  be  run  through  the  building  so  as  to  touch 
all  apartments,  the  effect  of  the  insulation  would 
be  nullified.  A  mistake  on  any  one  of  these  points 
is  very  likely  to  seriously  impair  the  value  of  the 
system. 

How  Flax-li-num  Fits  Into  the 
Specification 

Professor  F.  R.  Watson  in  his  text  book  “The 
Acoustics  of  Buildings”  publishes  the  results  of 
tests  run  to  determine  the  sound  absorption  co¬ 
efficients  of  insulating  materials.  The  co-efficient 
established  for  Flax-li-num  is  .55.  This  means 
that  55%  of  the  incident  sound  is  absorbed. 

Flax-li-num  has  the  qualities  that  endorse  it  as 
a  good  building  material.  There  is  built  into  it 
enough  raw  material  to  give  it,  in  its  semi-rigid 
felted  form,  the  strength,  durability  and  ease  of 
handling  that  make  it  a  product  liked  by  contrac¬ 
tors  and  workmen  on  the  job.  No  special  care 
need  be  exercised  in  its  handling  and  it  is  readily 
fitted  to  the  irregularities  in  construction  with  the 
least  labor  and  trouble. 


40 


Heat  Insulation  for  Houses 


Player  Piano  and  Harj)  Rooms  of  Lyon  &  Plealy  Music  Studios, 
Chicago,  Sound  Controlled  with  Flax-li-num. 

The  tlfird  and  perhaps  the  most  important  con¬ 
sideration  is  the  application.  In  examining  the 
specifications  that  follow,  it  will  be  noted  that  the 
jmri)ose  in  each  is  to  cut  off  absolutely,  one  floor 
from  the  other  and  one  side  of  each  partition  from 
the  other  with  a  thickness  of  Flax-li-num.  In  the 
brick  buildings  this  is  done  by  off-setting  the  wall 
at  the  ceiling  lines,  and  then  applying,  before  set- 
tingpartitions,  a  continuous  3^'''layerof  Flax-li-num 
to  the  under  side  of  the  ceiling  joists.  This  is 
further  protected  with  joist  pads  set  over  all  joists 
below  the  hnished  floor,  and  with  a  3^'' thickness  of 
Flax-li-num,  covering  the  rough  floor  like  a  carpet, 
the  hnished  hoor  to  be  laid  directly  over  this  14." 
Flax-li-num  without  furring  strips. 

In  the  stucco,  brick  veneer  or  frame  buildings 
where  the  studs  are  broken  at  the  ceiling  line,  plate 
pads  are  inserted  between  stud  and  plate  to  cut  off 
the  hoors,  and  these  form  a  continuous  laver  with 
the  3^''  hat  sheets  on  the  under  side  of  the  ceiling 
joists  as  in  the  solid  brick  building.  The  most 
difficult  type  of  building  to  deaden  is  that  in  which 


the  studdings  run  clear  through.  Here,  it  is  mani¬ 
festly  impossible  to  cut  oh  the  hoors  absolutely  one 
from  the  other,  and  the  only  practical  remedy  is  to 
insert  headers  of  Flax-li-num  between  the  studdings 
at  the  ceiling  line,  thus  closing  the  air  duct  between 
studdings,  but  not,  of  course,  stopping  the  direct 
transmission  through  the  studding  itself. 

Flax-li-num  hnds  uses  in  many  jobs  requiring 
special  treatment  for  sound  control. 

Flax-li-num  was  successfully  used  for  specially 
constructed  booths  for  the  Lyon  &  Healy  Com¬ 
pany,  prominent  Chicago  Music  house,  in  1915. 
The  following  statement  from  this  firm  indicates 
how  well  Flax-li-num  has  performed  in  this  un¬ 
usual  application,  leading  to  their  use  of  this  same 
material  again  in  1926: 

“For  the  past  eleven  years  FLAX-LI-NUM  has 
served  as  a  sound  eontroller  in  the  partitions  be¬ 
tween  our  talking  maehine  rooms  so  suceessfully 
that  we  are  installing  it  in  the  partitions  of  our  new 
player  piano  and  harp  rooms  that  are  now  being 
built. 

“Our  business  requires  sales  rooms  that  do  not 
transmit  any  sound  to  the  adjoining  rooms.  FLAX- 
LI-NUM  fills  this  requirement  so  well  that  we  shall 
continue  to  use  it  whenever  the  occasion  demands.” 

Acoustical  CotTcction 

The  majority  of  projects  in  which  problems  of 
aeoustics  arise  require  the  services  of  expert  acous¬ 
tical  engineers  in  their  solution.  The  Flax-li-num 
Insulating  Company  does  not  deal  in  generalities 
on  this  subject,  therefore,  and  offers  Flax-li-num 
on  its  record  of  proven  merit,  together  with  the 
services  of  trained  engineers  who  will  be  glad  to 
co-operate  with  architeets  and  engineers  on  the 
particular  projects  upon  which  they  are  working. 

Engineering  Service 

The  services  of  Flax-li-num  engineers  are  avail¬ 
able  to  arehiteets  and  engineers,  and  correspond- 
enee  is  invited  that  we  may  put  you  in  touch  with 
the  Flax-li-num  serviee  man  nearest  you. 


Heat  Insulation  for  Houses 


41 


Details — Sound  Control  Applications 

[See  Specifications  3-A,  5-A,  7-A,  on  Following  Pages] 


Party  Wall 

Framing  detail,  see  Plate  11 


Party  Wall  and  Floor 

FIREPROOF  construction' 


Party  Wall  and  Floor 

FRAME  construction  1/2"  Flax-Ii-num 

l"x2''  Furring  strips 
Plaster,  wood  lath 

Plate 

IV 

V4  "  Flax-Ii-num 


c 

Joist  Pads  ) 

>1/2" 

^  Floor  Joist  r^  1 

li-num  l)y|  ( 

l"x2"  Furring  strips  Plaster,  wood  lath 


Floor 


Steel  Joist 
Wire  Tie 
Wood  StripNy 


1"  Flax-li-nutn 


Plate 

V 


Furring  Strip.  Metal  lath  and  plaster 


STEEL 


Metal  lath  and  plaster 


Plate 

VI 


Party  Wall 

STEEL  CONSTRUCTION 


42 


Heat  Insulation  for  Houses 


Screened 

Louvre 


1"  on  Ceiling 
for  Roof  Insulation 


Sheathing 
lax-li-num 
Paper 
Air  Space 
Brick 


Heat  Insulation  for  Houses 


43 


Sound  Control,  Side  Wall  and  Roof  Insulation  where 

Studding  IS  Broken  at  Ceiling 

(Platform  Construction) 

Standard  Specification  No.  3-A 

[As  Per  Detail  on  Opposite  Page,  Also  Page  41] 

SOUND  CONTROL 

(1)  Materials:  Shall  be  3^"  Flax-li-niim  flat  sheets,  3^"  Flax-li-num  Joist  and 
Plate  Pads,  and  3^"  Flax-li-num  flat  sheets,  manufactured  by  the  Flax-li-num 
Insulating  Company,  St.  Paul,  Minn. 

(2)  Application:  Before  placing  joists  all  top  plates  shall  be  covered  with  3^" 
Flax-li-num  Plate  Pads  (the  width  of  the  plates).  Flax-li-num  Joist  Pads 
3/2^^x3"x3'  are  to  be  placed  on  top  edge  of  all  joists  and  headers  to  receive  floor¬ 
ing,  which  is  to  be  laid  diagonally  and  tight.  All  lower  plates  are  to  be  placed 
on  }/2'  Flax-li-num  Plate  Pads,  which  will  project  on  each  side  of  the  plates 
on  partition  walls,  and  on  the  inside  of  outside  walls,  to  receive  grounds 
for  lath  and  plaster.  Before  lathing,  ceiling  of  lower  floors  shall  be  covered 
with  ]/2'  Flax-li-num  flat  sheets  applied  to  the  bottom  edge  of  the  ceiling  joists, 
all  joints  to  be  well  fitted  and  butted  tight  (to  receive  end  joints,  1x2  headers 
shall  be  placed  between  the  joists) .  Headers,  joist  dimensions,  shall  be  placed 
between  the  joists  over  all  bearing  sound  controlled  partitions.  Extra  joist 
shall  be  placed  directly  over  and  below  where  sound  controlled  partitions 
parallel  the  joists.  Under  floors  are  to  be  covered  with  a  continuous  thickness 
of  3^"  Flax-li-num  fitted  tight  against  the  plate  pads  and  finished  floor  is  to  be 
laid  directly  over  Flax-li-mim  (no  furring  strips) . 

(3)  Party  Partition  Sound  Control  Application,  see  paragraph  No.  3,  Specification 
7-A,  page  45,  and  Details  1,  2  and  4,  page  41. 

ROOF  INSULATION 

(J)  Material:  Shall  be  V  Flax-li-num  flat  sheets,  manufactured  by  the  Flax-li- 
num  Insulating  Co.,  St.  Paul,  Minn. 

(5)  Application:  Before  placing  partitions,  1"  Flax-li-num  flat  sheets  shall  be 
applied  to  the  under  side  of  the  top  floor  ceiling  joists,  to  be  butted  tight 
against  plate  and  ribbon  board  and  furred  out  over  joists  with  lx2’s  for  lath 
and  plaster.  At  top  floor  ceiling  line,  headers,  stud  dimension,  shall  be  placed 
between  studs. 

SIDE  WALL  INSULATION 

(6)  Material:  Shall  be  3^"  Flax-li-num  flanged  or  flat  sheets,  manufactured  by 
the  Flax-li-num  Insulating  Co.,  St.  Paul,  Minn. 

(7)  Application  (1):  Flanged  Flax-li-num  shall  be  applied  in  accordance  with 
paragraph  No.  2,  Specification  13-A,  page  33. 

(8)  Application  (2):  From  foundation  to  top  floor  ceiling  line  34"  Flax-li-num  flat 
sheets  shall  be  applied  to  the  outer  side  of  the  sheathing.  Flax-li-num  shall 
be  covered  with  a  good  grade  of  asphalt  saturated  paper  and  furred  out  over 
studding  with  lath.  End  and  side  joints  are  to  be  butted  tight.  x4bove  top 
floor  ceiling  line  fur  outside  of  sheathing  with  lx2’s  and  lay  up  walls. 


44 


Heat  Insulation  for  Houses 


Screened 

Louvre 


1"  on  Ceiling 
for  Roof  Insulation 


/"A- 

END  JOINT 


Flax-li-num 

Headers 

Very  Important 


Mt 


':.F  ^  ^ 


?  -a. 


Heat  Insulation  for  Houses 


45 


Sound  Control,  Side  Wall  and  Roof  Insulation  where 
Studding  is  not  Broken  at  Ceiling  Line 

(Balloon  Construction) 

Standard  Specification  No.  7-A 

[As  Per  Detail  on  Opposite  Page,  Also  Page  41] 

SOUND  CONTROL 

(1)  Materials:  Shall  be  Flax-li-num  flat  sheets,  ]/2'  Flax-li-num  Joists  and 
Plate  Pads,  3^"  Flax-li-num  headers  and  Flax-li-num  flat  sheets,  manu¬ 
factured  by  the  Flax-li-num  Insulating  Co.,  St.  Paul,  Minn. 

{2)  Floor  Sound  Control  plication:  Flax-li-num  Joist  Pads  3/2^^x8"x3'  to  be 
placed  on  top  edge  of  all  joists  to  receive  under  flooring  which  is  to  be  laid 
diagonally  and  tight.  At  ceiling  line  and  at  floor  line  above,  on  all  floors,  3^" 
flanged  Flax-li-num  headers  are  to  be  fitted  tightly  between  studdings  in  such 
a  manner  as  to  completely  close  openings.  Before  lathing,  ceiling  of  lower 
floors  shall  be  covered  with  a  continuous  layer  of  3^"  Flax-li-num  flat  sheets 
nailed  to  under  side  of  joists.  All  joints  shall  be  fitted  and  butted  tight  against 
Flax-li-num  headers  which  are  between  studdings.  Under  joists  Flax-li-num 
shall  be  furred  out  with  1x2' s  for  lath  and  plaster. 

(3)  Party  Wall  Control  Application:  (See  Details  1,  2  and  4,  page  41.)  Lay 
3/^"x4"  Flax-li-num  pads  on  sleepers  below  partitions  before  placing  floor 
joists.  Cut  off  corners  of  joists  so  that  joists  from  one  side  of  partition  will 
not  touch  floor  on  the  other  side.  Place  3^"x6"  Flax-li-num  pads  between 
joists  that  support  floor  on  one  side  of  partition  and  joists  that  support  floor 
on  the  other  side.  Insert  wood  headers,  joist  dimension,  between  joists 
directly  under  partition,  separating  headers  from  the  joist  with  3^"x3"  Flax- 
li-num  pad.  Lay  3^"x4"  Flax-li-num  pads  over  these  headers  and  inter¬ 
sections  of  joists  and  lay  plate  directly  on  pads.  Apply  3^"  Flax-li-num  sheets 
to  partition  on  both  sides  running  Flax-li-num  down  to  and  butting  against 
Flax-li-num  pads  under  plate. 

ROOF  INSULATION 

(4)  Material:  Shall  be  1"  Flax-li-num  flat  sheets,  manufactured  by  the  Flax-li- 
num  Insulating  Co.,  St.  Paul,  Minn. 

(5)  Application:  Before  placing  partitions  1"  Flax-li-num  flat  sheets  shall  be 
applied  to  the  under  side  of  the  top  floor  ceiling  joists,  to  be  butted  tight 
against  joist  and  ribbon  board  and  furred  out  over  joists  with  lx2’s  for  lath 
and  plaster.  At  top  floor  ceiling  line,  headers,  stud  dimension,  shall  be 
])laced  between  studs. 

SIDE  WALL  INSULATION 

(6)  Material:  Shall  be  3^"  Flax-li-num  in  flat  sheets  32  inches  wide,  manu¬ 
factured  by  the  Flax-li-num  Insulating  Co.,  St.  Paul,  Alinn. 

(7)  Application:  From  foundation  to  top  floor  ceiling  line  F'lax-li-num  flat 
sheets  shall  be  applied  to  the  outer  side  of  the  sheathing.  Flax-li-num  shall 
be  covered  with  a  good  grade  of  asphalt  saturated  paper  and  furred  out  over 
studding  with  lath.  All  joints  to  be  butted  tight.  Above  top  floor  ceiling 
line  fur  with  lx2’s  and  lay  up  wall. 


46 


Heat  Insulation  for  Houses 


Heat  Insulation  for  Houses 


47 


Sound  Control  and  Roof  Insulation  where  Outside 
Walls  are  of  Brick  or  Hollow  Tile 

Standard  Specification  No.  5-A 

[As  Per  Detail  on  Opposite  Page,  Also  Page  41] 

SOUND  CONTROL 

(1)  Materials:  Shall  be  Flax-li-num  flat  sheets,  3^"  Flax-li-ntim  Joist  and 
Plate  Pads  and  Flax-li-num  flat  sheets,  manufactured  by  the  Flax-li-num 
Insulating  Company,  St.  Paul,  Alinn. 

(2)  Floor  Deadening  Application:  At  ceiling  line  build  wall  offset  two  inches  in 
from  wall  line  and  height  of  joists,  making  top  of  offset  full  and  plumb  with 
top  of  joists. 

Place  Flax-li-num  Joist  Pads  3^"x3"x3'  on  top  edge  of  ceiling  joists,  also  over 
the  wall  projections,  to  receive  under  flooring,  which  shall  be  laid  diagonally 
and  tight. 

All  ceilings  are  to  be  covered  with  a  layer  of  3^"  Flax-li-num  applied  to  under 
side  of  joists.  All  joints  to  be  well  fitted  and  butted  tight.  Fur  out  with 
1x2 ’s  over  Flax-li-num  to  receive  lath  and  plaster. 

Over  rough  flooring  lay  3^"  Flax-li-num  flat  sheets  fitted  tight  against  Plate 
Pads  at  partitions.  Finished  floors  to  be  laid  directly  on  3^"  Flax-li-num 
(no  furring  strips). 

(3)  Party  Partition  Deadening  Application:  Lower  plates  in  partitions  shall  be 
placed  on  3^"  Flax-li-num  Plate  Pads  projecting  on  each  side  of  plate. 
Upper  Plates  shall  be  covered  with  ]/^"  Flax-li-num  Plate  Pads.  Both  sides 
of  all  deadened  partitions  shall  be  covered  with  a  continuous  layer  of  3^" 
Flax-li-num,  which  shall  be  butted  tight  to  Plate  Pads  on  top  and  bottom. 

Fur  out  with  lx2’s  over  Flax-li-num  to  receive  lath  and  plaster.  Place  wood 
headers,  joist  dimension,  between  joists  on  all  deadened  partitions.  Place 
extra  joist  directly  over  and  below  deadened  partitions  where  these  parallel 
the  joists. 

ROOF  INSULATION 

(4)  Materials:  Shall  be  1"  Flax-li-num  flat  sheets,  manufactured  by  the  Flax- 
li-num  Insulating  Co.,  St.  Paul,  Alinn. 

(5)  Application:  Cover  ceiling  of  top  floor  with  1"  Flax-li-num  in  flat  sheets 
applied  to  the  under  side  of  the  ceiling  joists.  Flax-li-num  to  be  run  under 
wall  offset  and  butted  tight  to  outside  walls.  Fur  out  over  Flax-li-num  with 
1x2  strips  to  receive  lath  aud  plaster. 

SIDE  WALL  INSULATION 

See  paragraphs  1,  2,  and  3.  Specification  11-A,  page  37.  For  details  of 
sound  control  in  Fireproof  Construction  for  floors  and  party  walls  see  Plates 
3,  5,  and  G,  page  41. 


48 


Heat  Insulation  for  Houses 


Industrial  Roof  Insulation 


E  build  our  side  walls  strong  and  thick;  we  build  our  roofs  just  strong 
enough  to  be  self  supporting  with  a  reasonable  margin  of  safety. 

What  is  the  modern  industrial  roof  ?  Four  inches  of  concrete  with  five 
plies  of  roofing,  or  two  inches  of  lumber,  with  a  similar  covering,  or 
again  steel  plates,  with  waterproof  covering.  These  materials  make  excellent  roofs 
from  every  point  of  view  except  that  of  insulation.  They  are  strong,  watertight,  and 


durable,  but  they  do  not  keep  out  the  cold,  hold  in 
the  heat  or  prevent  condensation. 

Concrete  and  wood  both  conduct  heat  readily, 
so  readily,  in  fact,  that  l"of  Flax-li-num  is  equiva¬ 
lent,  in  heat  resistance,  to  5  inches  of  wood  plank¬ 
ing  or  21  inches  of  concrete.  Roofs  cannot  be 
built  in  these  thicknesses,  yet  they  must  equal  them 
in  heat  transmission.  From  a  construction  stand¬ 
point,  Flax-li-num  simplifies  your  roof  problem  by 
the  insertion  of  a  relatively  thin  material,  light  in 
weight,  durable  and  lasting  in  quality,  and  equal 
in  transmission  to  a  much  heavier  roof. 

Again,  the  principle  of  “Convection”  makes 
roofs  the  vulnerable  point  of  construction.  Con¬ 
vection  simply  means  that  heated  air  rises  and 
seeks  to  escape  confinement,  while  cold  air  settles 
toward  the  floor  or  ground.  This  means  that  the 
air  you  pay  to  heat,  is  constantly  seeking  ways  of 
escape ;  to  rise  through  the  ceiling  and  roof  of  every 
building  to  the  outside  air.  This  constant  cir¬ 
culation  of  air,  which  conveys  heat  to  the  roof, 
superheats  the  atmosphere  at  that  point.  Hence, 
even  though  roofs  offered  equal  protection  against 
heat  transmission  as  walls,  more  heat  would  escape 
through  roofs  than  through  side  walls. 

Roof  insulation  protects  against  heat  loss  in 
winter,  but  it  also  protects  against  heat  entrance 
in  summer.  The  superheating  of  factories,  necessi¬ 
tating  a  curtailment  in  summer  production,  is 
eliminated  by  insulating  the  roof.  This  protec¬ 
tion  against  summer  heat  is  vitally  essential  in  one. 
two  and  three  stoiy  factories,  where,  perhaps  one- 
third  or  one-half  of  the  total  floor  space  may  be 
affected  during  the  extremelv  hot  weather. 

O  t/ 


It  is  an  actual  fact  that  instead  of  a  superheated 
interior  atmosphere,  the  interior  temperature  under 
roofs  insulated  with  Flax-li-num  may  be  held  10  to 
15  degrees  lower  than  the  outside  temperature. 
Economy  through  year  round  use  of  floor  space  is 
good  building  and  good  management.  If  space 
otherwise  available  only  for  storage,  can  be  turned 
into  more  productive  channels,  costs  must  neces¬ 
sarily  decline.  Even  where  there  is  no  cessation 
of  operation  in  the  hot  weather,  the  output  is  cur¬ 
tailed  by  inefficiency  in  personnel  due  to  the  heat. 
An  increase  in  efficiency  of  workers  is  possible 
simply  by  building  into  the  plant  the  coolness  of 
the  refrigerator  car. 

Roof  insulation  effects  not  only  fuel  economy, 
but  personnel  economy.  It  contributes  to  that 
thing  for  which  we  are  striving,  greater  personnel 
efficiency,  larger  production,  less  waste,  and  this 
service,  though  difficult  to  measure  in  dollars  and 


Heat  Insulation  for  Houses 


49 


Flax-U-num  Sheets  Being  Laid  Out  On  The  Boof  Deck 
Preparatory  To  Mopping. 


cents,  is  perha})s  as  great  as  the  winter  fuel  saving 
effected  bv  Flax-li-num. 

t. 

Insulation  angnients  the  ventilating  system  and 
the  two  must  be  combined  to  create  ideal  con¬ 
ditions.  If  there  is  no  control  over  the  escape  of 
heat  or  cold,  the  best  ventilating  system  cannot 


The  Semi-Rigid  Sheet  Of  Flax-li-nwm  Rolled  Back  White  The  Mopping 
Is  Being  Done.  Xote  How  Flax-li-num  Follows  The  Mop. 
Assuring  A  Firm  Bond  To  The  Roof  Deck. 


function  at  anything  approaching  maximum  ef- 
ficiencv. 

V 

The  following  specifications  cover  in  detail,  just 


how  Flax-li-num  is  applied  to  roofs  of  concrete, 
wood  and  steel.  There  is  also  given  on  page  53  a 
table  of  transmission  coefficients,  fuel  savings  and 
radiation  savings,  which  may  be  secured  by  the  use 
of  various  thicknesses  of  Flax-li-num. 

Flax-li-num  has  many  advantages  as  a  roof  in¬ 
sulation.  First:  Its  semi-rigid  form  allows  the 
sheets  to  be  rolled  down  into  the  hot  moi)ping 
closely  following  the  mop  and  thus  making  it  easy 
to  secure  a  good  bond  by  placing  the  Flax-li-num 
sheets  directly  into  hot  mopping  before  it  has  an 


The  Built-Up  Roof  Applied  Over  The  Flax-li-num — 
Completing  The  Job. 


opportunity  to  chill.  Second:  Flax-li-num  for 
roof  insulation  should  be  butted  tight — there  being 
no  contraction  or  expansion  in  the  Flax-li-num 
sheets,  they  can  be  placed  tightly  together,  thus 
forming  a  continuous  sheet  of  insulation  over  the 
entire  roof. 

The  semi-rigid  nature  of  Flax-li-num  makes  the 
sheets  easy  to  handle  without  breaking  or  cracking, 
and  there  is  practically  no  loss  from  spoilage. 

The  semi-rigid  nature  has  another  advantage. 
The  sheets  easily  conform  to  any  unevenness  on  a 
roof  deck,  such  as  concrete,  and  eliminates  any 
need  for  smoothing  off  such  decks.  Thus,  when  the 
Flax-li-num  sheets  are  rolled  down  into  the  hot 
mopping  you  are  assured  of  the  best  })ossible  bond. 


50 


Heat  Insulation  for  Houses 


Heat  Transmission  Values  for  Roofs 


■■r,-:-<^.:  -.0.  ■  ^ ^  <0 .;  -=:-■■  ■  /°  ;■  -V?r.-1 


Outside  Surface . So  =  4.20 

5-Ply  Tar  and  Gravel  Roof . C  =0.40 

1"  Flax-li-num  Insulation  . C  =0.28 

4"  Concrete  Slab . C  =  8.30 

Inside  Surface . Sr  =  1  30 


Development  of  Roof  Formula 

1  1 
K  = -  K  = - =  0.186 


1 

1 

/Xo 

Xi  \ 

1 

1  i 

^.125 

1 

4  \ 

—  + 

+  1 

(  -  + 

—  +  Etc.  1 

+  —  +  ( 

-  + 

+  I 

So 

Si 

\Co 

Cl  / 

4.2 

1.3  * 

V  .4 

.28 

8.3/ 

K  =  Total  heat  transmission  per  sq.  ft.  per  hour  per  deg.  Fahr.  tem¬ 
perature  difference. 

50  =  Outside  Surface  Coefficient. 

51  =  Inside  Surface  Coefficient. 


X  =  Thickness  of  material  in  inches. 

C  =  Conductivity  Coefficient  per  inch  of  thickness  per  sq.  ft.  per 
hour  per  deg.  Fahr. 


Insulating  Values  of  Some  Common  Building  Material* 


Material 

Surface  and 
Conductivity 
Factors 

Thickness 
In  Inches 

B.  T.  U. 

Transmission 
per  sq.  ft. 
per  hr. per  deg. 
F.  temp.  diff. 

Brick  Wall . 

So  =  3.90 

9'' 

.36 

Si  =1.30 

13" 

.28 

C  =5.00 

18" 

.22 

24" 

.18 

Concrete  Walls  or  Roof 

Deck . 

So  =  3.90 

2" 

.78 

Si  =1.30 

3" 

.72 

C  =8.30 

4" 

.66 

6" 

.56 

Windows . 

Single 

1.13 

Double 

.45 

6"  or  8"  Hollow  Tile  Roof. 

plus  2"  Concrete  plus 

8" 

.38 

Tar  and  Gravel  Roofing 

10" 

.36 

Flax-li-num . 

C  =0.28 

14" 

.367 

1" 

.245 

2" 

.134 

Magnesia  Board . 

1" 

.35 

2" 

.21 

4" 

.12 

*Value.s  obtained  from  Harding  &  Willard,  U.  of  Penn,  and  U.  of 
M  inn.,  shown  here  for  jmrposes  of  ready  comparison. 


The  data  given  here  are  taken  from  i-eliable  sources.  The 
heat  floAV  was  determined  by  actual  tests  on  a  practical  size 
section.  These  tests  check,  within  experimental  limits,  the 
results  which  can  be  computed  from  the  formula  derived  by 
Willard  and  Lichty,  Fmiversity  of  Illinois. 

It  is  difficult  to  get  reliable  results  on  the  coefficients  S  and 
So,  therefore,  only  those  tests  which  can  be  substantiated  are 
given. 

The  steam  radiator  emits  approximately  250  B.  t.  u.  per 
square  foot  per  hour.  The  steam  coil  emits  approximately 
275  B.  t.  u.  per  square  foot  per  hour  and  the  hot  water  radiator 
approximately  156  B.  t.  u.  per  square  foot  per  hour.  One 
pound  of  ice  will  give  up  approximately  144  B.  t.  u.  in  melting. 

The  total  heat  which  is  to  be  supplied  per  hour  can  be  com¬ 
puted  as  follows: 

H  =  (KrC  +  KwW +KgG  -h0.02VX)  (T— To) 

For  heat  loss  thru  roof 
Hr  =  KrR  (Ti— To) 

AYhere  H  =  Total  heat  in  B.  t.  u.’s  of  entire  heated  space. 

Hr  =  Total  heat  thru  roof  in  B.  t.  u.’s. 

R  =  Roof  surface  in  square  feet. 

W  =  Wall  surface  in  square  feet. 

G  =  Glass  surface  in  square  feet. 

V  =  Volume  of  air  in  cubic  feet. 

N  =  Number  of  air  changes. 

N  =  2  for  factories,  1  to  2  for  schools  and  public  pla¬ 
ces.)^  to  1  for  storage. 

Ti  =  Inside  temperature  (Breathing  line). 

T  =  Inside  temperature  under  roof.  (Over  10  foot 
high  roof,  add  15  to  25%  to  inside  temp.). 

To  =  Outside  temperature. 

Kr  =  Heat  transmission  constant  for  roof. 

Kw  =  Heat  transmission  constant  for  walls. 

Kg  =  Heat  transmission  constant  for  glass. 

0.02  =  B.  t.  u.  to  raise  1  cubic  foot  of  entering  air  1 
degree  F. 

The  temperature  of  the  air  in  contact  with  the  under  side 
of  a  roof  is  much  higher  than  the  temperature  maintained  at 
the  breathing  line.  It  has  been  found  liy  exjieriment  that 
fifteen  to  twenty-five  per  cent  should  be  added  to  room  temper¬ 
ature  in  order  to  have  a  correct  rearling  for  temperature  at 
ceiling.  This  increase  has  not  been  taken  into  consideration 
in  the  comjmtations  on  the  following  page,  but  should  be 
applied  for  rooms  over  ten  feet  high. 


Heat  Insulation  for  Houses 


51 


Chart  Showing  Relative  Humidity  Which  May  be  Carried  Under 
Various  Roof  Decks  without  Condensation  on  Their  Under  Surface 


NOTE: — All  curves  are  based  upon  70°  F.  dry  bulb  temperature.  For 
any  other  appreciably  different  dry  bulb  temperature  a  correction  should 
be  made  to  the  relative  humiflity  found  by  these  curves. 


CONCRETE  DECKS - 

No.  1 — Four  inch  concrete  slab,  bare. 

No.  2 — Four  inch  concrete  slab,  plus  5-ply  roofing. 

No.  3— F  our  inch  concrete  slab,  plus  1"  Flax-li-num,  5-ply  roofing 
No.  4 — Four  inch  concrete  slab,  plus  2"  Flax-li-num,  5-ply  roofing. 

WOOD  DECKS - 

No.  5 — One  and  three-eighths  T.  &  G.  spruce  plank  plus,  5-ply 
roofing. 

No.  6 — One  and  fhree-eighths  T.  &  G.  spruce  plank  plus,  1''  Flax- 
li-num.  plus  5-ply  roofing. 

No.  7 — One  and  three-eights  T.  &  (i.  spruce  plank  plus  2"  Flax- 
li-num,  plus  5-ply  roofing. 

No.  8 — Two  and  three-eighths  T.  &  G.  spruce  plank  plus  5-ply 
roofing 

STEEL  DE('KS - - 

No.  9 — Steel  deck  and  5-ply  built-up  roof  (no  insulation) 

No.  10 — Steel  deck  with  one-half  inch  Flax-li-num  and  5-j)ly  roof. 
No.  11 — Steel  deck  with  1  inch  Flax-li-nnm  and  5-ply  roof. 

In  homes,  schools,  factories,  theatres  or  wherever  a  humidity  to  encourage 
the  best  of  health  or  the  best  condition  of  goods  is  essential,  it  is  desirable  to 
retard,  to  the  greatest  degree,  the  penetration  of  moisture  into  the  material 
used  as  insulation.  It  is  just  as  desirable  to  prevent  condensation  upon  a 
ceiling.  This,  of  course,  can  be  accomplished  only  by  retaining  a  surface 
temperature  above  that  of  conden.sation  at  a  given  humidity 

.According  to  the  Forest  Products  Laboratory,  it  is  impossible  to  absolutely 


waterproof  a  material.  It  is,  however,  possible  to  retard  the  rate  of  pene¬ 
tration  of  the  moisture  and  the  prevention  of  coiiflensation  heafls  off  many  of 
the  difficidties  that  would  otherwise  arise. 

The  curves,  shown  on  this  page,  determined  by  F.  R.  Shehlon  &  Sons  of 
Providence,  R.  L,  in  1917,  for  Textile  Mills,  will  show  the  roof  construction 
necessary  to  prevent  condensation  at  a  given  humidity.  The  following 
illustration  will  show  the  necessity  of  insulation  to  prevent  condensation. 

EXAMPLE:  It  is  desired  to  maintain  a  humidity  of  65%  with  a  temper¬ 
ature  of  50  degrees  F.  for  provisions.  The  outside  temperature  will  reach 
—20°  F.  The  total  temperature  difference  then  is  70°.  Now  run  a  line  per¬ 
pendicular  to  the  base  at  05%  relative  humidity,  continue  this  line  until  it 
intercepts  the  70°  line.  Curve  11  will  give  us  the  recpiired  j)rotection.  If 
our  inside  temperature  is  70°  F.  instead  of  50°  as  above,  and  the  outside 
temperature  en-20°  F.,  we  would  have  a  heat  head  of  90°  F.  Now,  with  a 
humidity  of  65%,  our  intersection  wonld  be  to  the  riglit  of  curve  11  on  the 
90°  heat  head  line.  With  this  condition,  it  would  be  necessary  to  increase 
the  amount  of  insulation  to  a  point  where  the  value  of  the  roof  would  equal 
that  of  curve  3. 

There  are  three  factors  involved  in  these  determinations,  first:  the  out¬ 
side  temperature;  second:  the  “heat  head”  or  tem{)erature  difference 
between  the  outside  and  inside  of  the  roof;  and  third;  tlie  relative  humidity 
to  be  maintained.  It  is  clear  that  where  the  outside  and  inside  temperatures 
correspond  exactly,  there  will  be  no  condensation  till  the  air  reaches  a  satu¬ 
ration  of  100%.  The  ideal  insulating  material  would,  then,  support  100% 
humidity  under  any  “heat  head”  and  the  “curve  of  the  perfect  insulator” 
shown  on  the  chart  is  consequently  a  straight  line  at  100%. 

In  protecting  against  condensation  it  is  a  grave  mistake  to  figure  avei-age 
temperatures.  Even  on  an  unprotected  roof,  conden.sation  does  not  neces¬ 
sarily  occur  all  the  time.  If,  however,  it  occurs  four  or  five  times  a  year,  the 
resulting  damage  may  be  very  sev'ere.  Basing  conden.sation  comj)utations 
on  extremef!  of  temperature  is,  therefore,  not  extravagance,  but  common 
sense.  This,  if  an  extreme  temperature  of  20  degrees  below  zero  is  probable 
during  the  winter,  then,  figuring  70  degrees  as  the  interior  temperatur*'  at 
the  ceiling  line  (the  warmest  portion  of  the  building),  a  “heat  heafl”  of  90 
degrees  will  be  a  fair  basis  upon  which  to  figure  condensation.  'Fo  insulate 
for  an  average  winter  temperature  of,  say  2()  degrees  above  zero,  in  this  case, 
would  mean  that  whenever  the  temperature  got  below  this  mark,  conden¬ 
.sation  would  take  place.  It  would  be  poor  economy  and  faulty  construction. 


52 


Heat  Insulation  for  Houses 


Heat  Transmission  of  Wood  Decks  with 
Suspended  Ceilings 


Uninsulated 


Insulated 
Flax-li-num 
Keyboard 
Plaster  Base 


5  Ply  Built-Up  Roof 
Roof  Boards 


Roof  Joists 


Suspended  Ceiling 
Lath  86  Plaster 


Transmission  K=.284 


5  Ply  Built-Up  Roof 
Roof  Boards 
Roof  Joists 


Suspended  Ceiling 


Plaster  On  Flax-li-num 
Keyboard 


Transmission  K=.196 


Insulated 
1  inch 
Flax-li-num 


5  Ply  Built-Up  Roof 
I  Roof  Boards 
Roof  Joists 
Suspended  Ceiling 
1"  Flax-li-num 


l"x2"  Furring 
Lath  86  Plaster 


Transmission  K — .132 


Heat  Insulation  for  Houses  53 


Radiation  and  Heat  Losses 

on  Industrial  Roofs 

CONCRETE  DECK 

Without 

Insulation 

With  I^-inch 
Flax-li-nutn 

With  1-inch 

Flax-H-num 

With  ^-inch 

Flax-li-num 

Insulation 

Insulation 

Insulation 

*HEAT  TRANSMISSION  for  a  4"  concrete  deck,  plus  5-ply  built- 
up  roof . 

.557 

.279 

.185 

.112 

HEAT  LOSS  in  B.  t.  ids  i)er  1,000  square  feet  for  a  40°  E.  difference 

in  temoerature  for  a  heating  season  of  210  days . 

HEAT  LOSS  IN  POUNDS  OF  COAL  per  1,000  square  feet  of  roof 
surface  for  40°  difference  in  temperature  for  210  days  (available  heat 
])er  pound  of  coal  6,500  B.t.u’s) . 

112,224,000 

56,280,000 

37,464,000 

22,596,000 

17,265 

8,659 

5,764 

3,476 

RADIATION  REQUIRED  for  1,000  square  feet  of  roof  when  a 
temperature  of  70°  F.  is  maintained  under  roof  with  outside  tem¬ 
peratures  as  indicated. 

(275  B.  t.  u’s  per  square  foot  of  steam-coil  radiation) 

Outside  temperature  0°  F . 

141 

71 

47 

28 

Outside  temperature  -10°  F . 

161 

81 

54 

33 

Outside  temperature  -20°  F . 

182 

91 

61 

37 

WOOD  DECK 

Without 

Insulation 

With  I^-inch 
Flax-li-num 

With  1-inch 

Flax-li-num 

With  'J-inch 
Flax-li-num 

Insulation 

Insulation 

Insulation 

*HEAT  TRANSMISSION  for  a  2"  wood  deck  roof,  plus  5-pIy 

built-up  roof . 

HEAT  LOSS  in  B.  t.  u’s  per  1,000  scjuare  feet  for  a  40°  F.  difference 

.380 

.227 

.161 

.102 

in  temperature  for  a  heating  season  of  210  days . 

HEAT  LOSS  IN  POUNDS  OF  COAL  per  1,000  square  feet  of  roof 
surface  for  40°  difference  in  temperature  for  210  days  (available 
heat  per  pound  of  coal  6,500  B.  t.  u’s) . 

76,608,000 

45,789,000 

32,482,000 

20,563,000 

11,785 

7,040 

5,000 

3,165 

RADIATION  REQUIRED  for  1,000  square  feet  of  roof  when  a 
temperature  of  70°  F.  is  maintained  under  roof  with  outside  tem¬ 
perature  as  indicated. 

(275  B.  t.  u’s  per  square  foot  of  steam-coil  radiation) 

Outside  temperature  0°  F . 

97 

58 

41 

26 

Outside  temperature  -10°  F . 

111 

66 

47 

30 

Outside  temperature  -20°  F . 

124 

75 

53 

34 

STEEL  DECK 

Without 

Insulation 

With  J-^-inch 

Flax-li-num 

With  1-inch 
Flax-li-num 

With  s2-inch 
Flax-li-num 

Insulation 

Insulation 

Insulation 

*HEAT  TRANSMISSION  for  a  steel  deck  roof,  plus  5-ply  built-up 
roof . 

.94 

.35 

.216 

.122 

HEAT  LOSS  in  B.  t.  u’s  per  1,000  square  feet  for  a  40°  F.  difference 

in  temperature  for  a  heating  season  of  210  davs . 

HEAT  LOSS  IN  POUNDS  OF  COAL  per  1,000  square  feet  of  roof 
surface  for  40°  difference  in  temperature  for  210  days  (available 
heat  per  pound  of  coal  6,500  B.  t.  u’s) . 

189,504,000 

70,560,000 

43,545,600 

24,620,000 

29,154 

10,856 

6,699 

3,790 

RADIATION  REQUIRED  for  1,000  stiuare  feet  of  roof  when  a 
temperature  of  70°  F.  is  maintained  under  roof  with  outside  tem¬ 
peratures  as  indicated. 

(275  B.  t.  u’s  per  square  foot  of  steam-coil  radiation) 

Outside  temperature  0°  F . 

239 

89 

55 

31 

Outside  temperature  -10°  E . 

274 

102 

63 

36 

Outside  temperature  -20°  F . 

308 

115 

71 

40 

*B.  t.  u.  per  square  foot  per  hour  per  degree  F.  temperature  difference. 

54 


Heat  Insulation  for  Houses 


Detail 
No.  1 


5  Ply  Built  Up  Roof 
Roofing  Composition,  Mopping 
Flax-li-num 
Mopping 
Priming 
Concrete 


Detail 
No.  2 


5  Ply  Built  Up  Roof 
Roofing  Composition,  Mopping 
Flax-li-num 
Water  Proof  Paper 
Roof  Boards 


Detail 
No.  3 


5  Ply  Built  Up  Roof 
Roofing  Composition,  Mopping 
Flax-li-num 
Roof  Boards 


Heat  Insulation  for  Houses 


55 


Heat  Insulation  for  Flat  Roof  Decks 

Standard  Specification  No.  2-A 

[As  Per  Detail  on  Opposite  Page] 

CONCRETE  DECK 
(Detail  No.  1) 

(1)  Roof  Deck:  (Concrete):  Shall  be  finished  smooth,  without  depressions  that 
could  hold  water,  properly  graded  to  drains,  and  thoroughly  dry  and  clean. 

(2)  Materials:  Shall  be  1"  Flax-li-num,  manufactured  by  the  Flax-li-num  In¬ 
sulating  Company,  St.  Paul,  IVIinn.  A  good  grade  Roofing  Comjjosition  or 
Cement  shall  be  used  for  all  moppings.  Roofing  as  specified  elsewhere. 

(3)  plication:  Where  asphalt  roofing  composition  is  used  prime  concrete 
surface,  using  at  least  one  gallon  of  priming  per  100  stpiare  feet.  Where  coal 
tar  pitch  roofing  composition  is  used  priming  not  necessary.  Mop  thoroughly 
over  deck  and  lay  Flax-li-num  into  hot  mopping,  pressing  down  into  mopping 
in  workmanlike  manner.  Butt  all  ends  tightly  together  to  insure  proper 
insulation  at  joints.  Mop  over  Flax-li-num  thoroughly  and  lay  roof  over 
hot  mopping. 

WOOD  DECK  WHERE  EXCESSIVE  CONDENSATION  IS  A  FACTOR 

(Detail  No.  2) 

(4)  Roof  Deck:  (Wood) :  Shall  be  well  seasoned,  narrow  width  lumber,  prop¬ 
erly  nailed  and  free  from  wide  cracks,  knots  and  imperfections.  Roof  surface 
shall  be  smooth,  clean  and  properly  graded  to  outlets,  without  depressions 
which  could  hold  water.  Cant  strips  shall  be  applied  at  fire  walls  and 
elevations. 

(5)  Materials:  Shall  be  1"  Flax-li-num,  manufactured  by  the  Flax-li-num  In¬ 
sulating  Company,  St.  Paul,  Minn.  An  approved  Roofing  Composition 
shall  be  used  for  all  moppings.  A  thorouglily  saturated  water-proof  felt 
shall  be  used  under  the  Elax-li-num. 

(6)  *  Application:  Lay  one  thickness  of  water-proof  felt,  overlapping  joints  at  least 

4  inches.  Lay  Flax-li-num  sheets  over  water-proof  felt,  butting  ends  and  sides 
carefully  to  insure  a  continuous  sheet  of  insulation.  Run  Flax-li-num  to  all 
walls  and  fit  tightly  around  all  openings  in  roof,  nailing  Flax-li-num  every  12 
inches  along  edges  with  large  head  roofing  nails.  Mop  entire  surface  thoroughly, 
using  sufficient  roofing  com])osition  to  water-proof  insulation. 

WOOD  DECK  UNDER  NORMAL  HUMIDITY  CONDITIONS 

(Detail  No.  3) 

(7)  Roof  Deck:  Same  as  Detail  No.  2. 

(8)  Materials:  Flax-li-num  mopping  and  roofing  same  as  Detail  No.  2.  Omit 
water-proof  paper  under  Flax-li-num. 

(9)  *  Application:  Same  as  above. 

*Iniportant:  See  Paragraph  4,  Page  .57. 


56 


Heat  Insulation  for  Houses 


The  need  of  Flax-li-num  on  steel  decks  is 
so  evident  that  it  need  hardly  be  argued.  In 
fact,  on  any  building  that  is  to  be  heated  (not 
taking  into  consideration  any  coal  savings), 
enough  is  saved  in  the  heating  plant  to  more 
than  pay  for  the  insulation;  in  other  words 
it  is  cheaper  to  build  a  building  with  it  than 
without  it.  For  example:  the  transmission 
on  a  steel  deck  with  three-ply  Built-Up  Roof 
is,  .94  B.t.u’s  per  hour,  per  square  foot,  per 
degree  temperature  difference.  Taking  a 
temperature  difference  of  70°  F.  (70°  under 
roof  and  0°  outside)  and  proportioning  the 
radiation  for  this  type  of  roof  without  insu¬ 
lation,  the  amount  of  direct  radiation  neces¬ 
sary  to  offset  the  heat  loss  for  1,000  square 
feet  of  roof  is  239  feet.  With  one-inch  Flax- 
li-num  the  transmission  would  be  .210  B.t.u’s 
per  hour,  per  square  foot  per  degree  temper¬ 
ature  difference  and  the  radiation  necessarv 
for  1,000  square  feet  of  roof  is  55  feet,  or  a 
saving  of  184  feet  of  radiation  on  each  1,000 
square  feet  of  roof  area. 


Heat  Insulation  for  Houses 


57 


Heat  Insulation  for  Steel  Deck  Roofs 

Standard  Specification  No.  14-A 

[As  Per  Detail  on  Opposite  Page] 


(1)  Boof  Deck:  Steel  properly  graded  to  drains,  and  thoroughly  dry 
and  clean. 


(2)  hisulating  Material:  Shall  be  1-inch  Flax-li-num  manufactured 
by  the  Flax-li-num  Insulating  Company,  St.  Paul,  Minn.  A 
good  grade  roofing  cement  shall  be  used  for  all  moppings.  Roof¬ 
ing  as  specified  elsewhere. 

(3)  Application:  Mop  thoroughly  over  steel  deck  with  Standard 
Grade  Roof  Composition  and  lay  Flax-li-num  into  hot  mopping, 
pressing  down  into  mopping  in  workmanlike  manner.  Butt  all 
ends  tightly  together  to  insure  proper  insulation  at  joints.  Run 
Flax-li-num  tight  to  all  walls  and  butt  tightly  at  all  openings  in 
roof.  Mop  over  Flax-li-num  thoroughly  and  lay  roof  into  hot 
mopping. 


(4)  Important:  Flax-li-num  must  be  laid  into  roofing  composition 


/  /  / 

Flashing  and  Cut-off  Detail  for 
Insulation  Under  Built-up  Roofs 

A 

This  detail  covers  the  application  of  insu¬ 
lation  in  connection  with  specifications  2-A 
and  14-A.  This  plate  shows  the  wood  strip 
laid  to  all  walls  for  nailing  flashing.  The 
cut-off  should  be  used  to  seal  off  the  Flax- 
li-num  in  areas  of  approximately  100  square 
feet,  and  should  also  be  used  to  close  up  the 
job  at  the  end  of  work  for  the  day. 

''///Z 

wood  strip  cut-ofi 

immediately  after  mopping, 
or  composition  will  become 
hard  before  sheets  are  laid. 
Do  not  lay  more  Flax-li- 
num  than  can  be  covered  in 
a  day.  All  edges  or  expos¬ 
ed  parts  of  Flax-li-num  to 
be  covered  with  cap  sheet 
mopped  to  deck,  and  reopen¬ 
ed  when  work  is  resumed. 
Run  insulation  tight  to  all 
walls  and  butt  tightly  at  all 
openings  in  roof,  flashing  as 
specified  elsewhere. 


58 


Heat  Insulation  for  Houses 


Flax-li-num  Test  Data 


Ill  considering  an  insulating  material  there  is  one 
imjiortant  factor  that  should  be  well  noted,  that  is, 
the  distinction  between  thermal  conductivity  and 
thermal  transmission.  These  values  differ  and  the 
one  can  not  substitute  for  the  other.  The  reason 
for  jiaying  close  attention  to  the  differences  is,  that 
insulating  materials  perform  differently  under  dif¬ 
ferent  methods  of  application  and  the  test  data 
should  be  apjilied  in  a  manner  that  will  give  correct 
values  for  the  entire  wall  or  roof  unit  when  com¬ 
pleted. 


Conductivity 

(’onductivity  represents  the  number  of  B.  t.  u.’s 
that  will  jiass  through  one  inch  of  thickness  of  an 
insulating  material,  per  scpiare  foot,  per  degree  F. 
jier  hour.  It  should  be  noted  that  the  heat  flow 
here  is  through  the  material  only  and  is  a  surface 
to  surface  measurement.  (See  hgure  1.) 

Ti  'ansmission 

The  term  transmission  as  used  here  represents 
the  number  of  B.  t.  u.’s  that  will  pass  through  one 
ineh  of  an  insulating  material  per  scpiare  foot,  per 
degree  F.  jier  hour,  and  includes  the  surface  re¬ 
sistances.  in  addition  to  the  thermal  conductivitv.* 

_ _  K- 

(See  hgure  t.) 

It  will  lie  noted  that  the  transmission  factor  is 
lower  than  the  conductivitv  factor.  Thus,  the 
insulating  value  of  a  material  so  applied  as  to  take 
advantage  of  the  surface  resistances  is  better  than 
though  the  same  material  were  apjilied  so  that  sur- 
faee  resistances  are  eliminated. 

Methods  of  Testing' 

Thermal  conductivitv  is  arrived  at  bv  the  hot 
jilate  method  of  testing.  Transmission  is  arrived 
at  by  the  hot  box  method,  as  well  as  by  computa¬ 
tions  from  hot  plate  results. 

*The  term  transmission  is  also  used  to  represent  the  total 
heat  travel  through  a  comiionnd  wall  or  roof  made  n])  of  va¬ 
rious  hnilding  materials  and  air  s])aces. 


The  illustrations  of  temperature  gradients  here 
shown,  (Figures  I  and 't)  plainly  indicate  the  differ¬ 
ence  in  results  obtained  bv  the  hot  box  and  the  hot 

t. 

plate  methods  of  testing. 

Hot  Box  Data--Tra7is7nission 

When  Flax-li-num  is  applied  between  studdings, 
midway  between  the  inner  and  outer  wall  units, 
or  on  ceilings,  with  furring  strips,  giving  air  spaces 
on  both  sides  of  the  insulation,  in  accordance  with 
the  specifications  shown  on  pages  31,  33,  and  35, 
the  transmission  factors  obtained  by  the  hot  box 
method  are  used.  For  the  standard  thicknesses 
of  Flax-li-num  these  values  are  as  follows: 

yT  Flax-li-num  .37 


V  Flax-li-num  .24 

The  above  transmission  co-efficients  are  in  ac¬ 
cordance  with  the  tests  as  published  in  Bulletin 
#3,  Engineering  Department  of  the  University  of 
Minnesota. 


Hot  Plate  Data--Co7iductivity 


When  Flax-li-num  is  so  applied  that  the  surface 
resistances  are  eliminated,  such  as  is  the  case  when 
the  material  is  used  for  roof  insulation,  mopped 
down  to  the  deck  and  covered  with  a  built-up  roof. 


Figure  I 


Wi 

i 

: 

Cold  Plate 

e 

i 

m 

w 

Hot  Plate 

$ 

r 

s>Wi.^ 

m 

Hot  Plate  Test  for 
Conductivity  “C” 


Figure  11 


Hot  Box  Test  for 
Transmission  “K” 


Heat  Insulation  for  Houses 


59 


the  conductivity  values  obtained  by  the  hot  plate 
method  are  used.  Hot  plate  tests  on  Flax-li-uum, 
as  })ublished  by  the  United  States  Bureau  of  Stand¬ 
ards,  give  a  conductivit}"  co-efficient  of  .3^2  per  inch 
of  thickness.  Computing  in  accordance  with  the 
method  approved  by  the  Bureau  for  determining 
the  actual  conductivitv  of  commercial  thicknesses, 
gives  the  following  values  for  the  standard  thick¬ 
ness: 

Flax-li-num  .56 
1'  Flax-li-num  .28 


All  of  the  computations  for  wall  sections  and 
roofs  covered  in  this  Bulletin,  are  based  upon  the 
proper  application  and  the  proi)er  co-efheient  as 
outlined  above  has  been  used. 

Caution:  When  considering  wall  or  roof  con¬ 
struction  the  transmission  or  eonduetivitv  factors 

t 

for  the  various  units  should  be  computed  on  the 
actual  thickness  in  which  each  unit  is  to  be  used. 
Care  should  be  taken  not  to  misinterpret  test  data 
of  Laboratories  which  are  always  given  upon  a  unit 
thickness  and  not  upon  the  thickness  of  the  mate¬ 
rial  as  actuallv  manufactured  and  used. 


Flax-li-num — Standard  Items 


Sheet  Sizes,  Sqjfare  Footage  and  Wei  ght 


Thickness 

I 

^orin  Width  Length 

Scj.  Ft.  i)er  Sheet 

34  Inch . 

.  Flanged 

. 1634  Inches 

.  8  Feet . 

. 11.00 

34  Inch 

Flanged 

1634  Inches 

9  Feet 

12.37 

34  Inch  . 

.  .Flanged 

. 1634  Inches 

. 10  Feet . 

. 13.75 

34  Inch  . 

.  .Flanged 

. 2434  Inches 

.  8  Feet . 

. 16.33 

34  Inch 

Flanged 

2434  Inches 

9  Feet 

18.37 

34  Inch  . 

.  .Flanged 

. 2434  Inches 

. 10  Feet . 

. 20.41 

34  Inch  . 

.  . Flat. . .  . 

. 32  Inches .  . 

.  8  Feet . 

. 21.33 

34  Inch 

Flat 

32  Inches 

9  Feet 

24.00 

34  Inch  . 

.  .Flat...  . 

. 32  Inches  .  . 

. 10  Feet . 

. 26.66 

34  Inch . 

.  . Flat. . .  . 

. 32  Inches  .  . 

.  8  Feet . 

. 21.33 

34  Inch 

Flat 

32  Inches 

9  Feet 

24.00 

34  Inch . 

.  Flat.  .  . 

. 32  Inches  .  . 

. 10  Feet . 

. 26.66 

1  Inch . 

.  .  Flat . 

. 32  Inches  .  . 

.  8  Feet . 

. 21.33 

1  Inch 

Flat 

32  Inches 

9  Feet 

24.00 

Ft anged  Ftax-ti-num 

Sound  Controt  Headers 

34  Inch . 

. . .  Flanged 

. 1634  Inches 

.  4  Inches . 

.  0.46 

34  Inch 

Flanged 

1634  Inches 

6  Inches 

0.69 

Ftax-ti-num  Sound  Controt  Joist  Pads 

34  Inch . 

.  .  .  Flat ... 

.  3  Inches. . 

.  3  Feet . 

.  0.75 

Ftax-ti-num  Sound  Controt  Ptate  Pads 

34  Inch . 

.  Flat. . . . 

.  4  Inches. . 

.  3  Feet . 

.  1.00 

34  Inch 

Flat 

6  Inches 

3  Feet 

1 .50 

Ft ax-li-n  u  m  Keyhoa  rd 

Furnished  in  two  sizes:  36"  x48"  and  36"  x  32"  (one-half  of  each  size  should  be  specified). 


Actual  weight  of  Flax-li-num  (not  to  be  confused  with  shipping  weights,  which  vary  with  mode  of  shipment). 

34  Inch —  40  lbs.  per  hundred  square  feet  1  Inch — 115  lbs.  per  hundred  square  feet 

34  Inch —  60  lbs.  per  hundred  square  feet  Keyboard — 125  lbs.  per  hundred  s([uare  feet 


Heat  Insulation  for  Houses 


library  ' 

UHlVERSlTfi 


F6| 


VALUE  OF  K  IN  B.  T.  U.  PER  SQUARE  FOOT  OF  EXPOSED  SURFACE  PER  DEGREE  FAHRENHEIT  PER  HOUR 


FLAX-LI-NUM  RADIATION  CHART  Based  on  Actual  Heat  Loss  Through  Building  Construction 


0.60 


0.58 


0.56 


0.54 


0.52 


0.50 


0.48 


0.46 


.34 


0.32 


0.30 


0.28 


0.26 


0.24 


0.18 


0.16 


0.14 


0.12 


0.10 


0.02 


Engineering  Department  FLAX-LI-NUM  INSULATING  CO.  St.  Paul,  Minnesota 


4 


Reference  Number 


0)  T) 

C  CO 

OKd. 


VALUE 
OF  X 


■  70— (—20)  ’ 

Follow  Reference  line  1.73  to  the  intersection 
of  horizontal  line  0.27  and  then  drop  vertically  to 
bottom  of  chart  and  read  number  of  square  feet 
of  wall  surface  per  square  foot  of  radiation,  which 


-=  274.6  sq.  ft.  of  rad.  required 


to  offset  heat  loss  through  wall. 

For  ceiling  follow  Reference  line  1.73  to  inter¬ 
section  of  horizontal  line  0.35;  then  drop  verti¬ 
cally  to  bottom  of  chart  and  read  number  of 
square  feet  of  radiation  which  is  4.8,  whence 

187.5  sq.  ft.  of  rad.  required  to  offset  heat 
loss  through  ceiling. 

(2)  For  glass  follow  Reference  line  1.73  to  horizon¬ 
tal  line  0.62,  then  drop  vertically  to  bottom  of 
chart  and  read  number  of  square  feet  of  glass 
surface  per  sq.  ft.  of  radiation,  which  is  2.6 
430 

whence  165.4  sq.  ft.  of  rad.  required  to 

offset  heat  loss  through  glass. 

For  infiltration  with  Reference  number  1.73 
one  square  foot  of  radiation  for  every  94.5  cubic 
feet  of  air.  (See  table  at  left.)  Then  with  num¬ 
ber  of  air  change  of  1  per  hour  we  have 

=  171.4  sq.  ft.  of  rad.  required  to  offset  heat 
loss  due  to  infiltration. 


T able  for  comput¬ 
ing  radiation  to 
offset  infiltration 


W 

WK 

WZ 

K 


Total  Radiation  required  =  274. 6 +  187.5 -)- 
165.4  +  171.4  =  798.9  square  feet.  Add  10  per 
cent  for  exposure.  Total  Radiation  =878.8 
square  feet. 


1  2  3  4  5  6  7  8  9  10  15  25  3U  49  59 

NO.  OF  SQUARE  FEET  OF  EXPOSED  BUILDING  SURFACE  PER  SQUARE  FOOT  OF  RADIATION 


30 


1 )  Reference  Number  =  I  ^  ^ 

Room  Temp.  -  Outside  Temp. 

Reference  Number  “Curve  Number. 

EXAMPLE; — Given  room  temp.  70°  F,  out¬ 
side  temp. — 20°F,  Hot  Water  radiation  installed 
'  to  give  off  156  B.  t.  u.  per  sq.  ft.  of  radiating  sur¬ 
face  under  above  conditions. 

House  has  1730  sq.  ft.  of  wall  surface.  Kw  = 
0.27.  Ceiling  surface  is  900  sq.  ft.  with  Kc  =  0.35. 
Glass  surface  is  430  sq.  ft.  with  Kg  =  0.62.  Cub¬ 
ical  content  is  16,200  cu.  ft. 

SOLUTION;— 

Reference  Number  =; 


'y^'sAfr  /Sms 


70 


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